:Northern line extension to Battersea

{{Further|Battersea Power Station}}

File:Battersea_Power_Station_in_London.jpg

Battersea Power Station was a coal-fired power station on the south bank of the River Thames in Nine Elms, Battersea. Built in two stages as a single building in the 1930s and 1950s, the power station closed in 1983. It is a Grade II* listed building, owing to its size, Art Deco interior fittings and decor, and design by architect Giles Gilbert Scott.{{Cite web |date=2007 |title=BATTERSEA POWER STATION, Non Civil Parish – 1357620 |url=https://historicengland.org.uk/listing/the-list/list-entry/1357620 |url-status=live |archive-url=https://web.archive.org/web/20210909142637/https://historicengland.org.uk/listing/the-list/list-entry/1357620 |archive-date=9 September 2021 |access-date=9 September 2021 |website=Historic England |language=en}}

The first major proposal to develop the site in the mid 1980s was for an indoor theme park, by the owners of Alton Towers.{{Cite web|last=Harrad|first=Tom|date=7 April 2016|title=How Battersea Power Station Almost Became London's Very Own Alton Towers|url=https://www.vice.com/en/article/bnkpj5/battersea-power-station-theme-park|url-status=live|access-date=9 September 2021|website=Vice|archive-date=9 September 2021|archive-url=https://web.archive.org/web/20210909142637/https://www.vice.com/en/article/bnkpj5/battersea-power-station-theme-park}} The theme park proposal included the 'Battersea Bullet', a dedicated British Rail shuttle train from London Victoria station to the theme park. Owing to the early 1990s recession, the project was cancelled.{{Cite book |last=Watts |first=Peter |title=Up in smoke: the failed dreams of Battersea Power Station |date=2016 |publisher=Paradise Road |isbn=978-0-9935702-0-9 |location=Richmond |oclc=948340667}} There were various other proposals, including offices, a shopping centre and a new football stadium for Chelsea FC, as the site passed through several different owners. However, it remained undeveloped for over 30{{nbsp}}years. The building was added to the Heritage at Risk Register in 1991, and the World Monuments Fund watch list in 2004.{{Cite web|date=February 2019|title=Battersea Power Station|url=https://www.wmf.org/project/battersea-power-station|url-status=live|access-date=14 September 2021|website=World Monuments Fund|language=en|archive-date=18 May 2021|archive-url=https://web.archive.org/web/20210518192027/https://www.wmf.org/project/battersea-power-station}}

The Northern line was last extended into South London in 1926, as part of an extension to Morden. In the 1980s, a southern extension of the Northern line to Peckham was proposed, as part of a review of potential extensions of Underground lines. The proposal was not implemented.{{Cite web|date=1988|title=Strategic Review 1988 – New Lines and Extensions – Northern Line Southern Extension|url=https://www.whatdotheyknow.com/request/244458/response/618034/attach/5/LUL%20Strategic%20Review%201988%20New%20lines%20and%20extensions%20Northern%20Line.pdf?cookie_passthrough=1|url-status=live|website=What Do They Know|publisher=London Underground|access-date=9 September 2021|archive-date=9 September 2021|archive-url=https://web.archive.org/web/20210909142639/https://www.whatdotheyknow.com/request/244458/response/618034/attach/5/LUL%20Strategic%20Review%201988%20New%20lines%20and%20extensions%20Northern%20Line.pdf?cookie_passthrough=1}}

Throughout the 2000s, no plans were considered for extending the Northern line, as the Public Private Partnership (PPP) to upgrade the Underground did not include provision for line extensions within the PPP contracts.{{Cite web|date=8 January 2003|title=Details of Tube modernisation plans unveiled|url=http://www.tubelines.com/news/releases/200602/20030108.aspx|archive-url=https://web.archive.org/web/20060519094016/http://www.tubelines.com/news/releases/200602/20030108.aspx|archive-date=19 May 2006|access-date=8 March 2021|website=Tube Lines}}{{Cite web|last1=Shawcross|first1=Valerie|last2=Livingstone|first2=Ken|date=7 March 2005|title=Transport Plan – Southward Extensions|url=https://www.london.gov.uk/questions/2005/0820|url-status=live|access-date=29 March 2021|website=Mayor's Question Time|archive-date=9 September 2021|archive-url=https://web.archive.org/web/20210909142647/https://www.london.gov.uk/questions/2005/0820}} Instead, the Northern line was to be upgraded with new signalling, and was proposed to be split into two separate lines by the mid 2020s following the completion of expansion work at Camden Town tube station.{{Cite CiteSeerX |date=November 2006|title=Transport 2025: Transport vision for a growing world city |citeseerx=10.1.1.135.5972|quote=A segregation of services would deliver simpler service patterns on the line. This will allow more trains to be run through both the West End and City branches – enabling 30tph services on the central London branches. This will provide roughly 25 per cent extra capacity and crowding relief on these busy sections. With the core infrastructure being capable of supporting these service patterns, the main requirements are some additional trains (and stabling) and station capacity improvements at Camden Town.}} Extensions of the Underground were being considered elsewhere in London, including a proposed extension of the Bakerloo line into south east London.{{Cite web|date=January 2007|title=Underground 2025 – South London Corridor Report January 2007|url=https://www.whatdotheyknow.com/request/244458/response/618034/attach/7/U2025%20SOUTH%20LONDON%20REPORT%20JANUARY%202007.pdf?cookie_passthrough=1|url-status=live|access-date=9 September 2021|website=What Do They Know|publisher=London Underground Limited Strategy and Service Development|archive-date=9 September 2021|archive-url=https://web.archive.org/web/20210909142648/https://www.whatdotheyknow.com/request/244458/response/618034/attach/7/U2025%20SOUTH%20LONDON%20REPORT%20JANUARY%202007.pdf?cookie_passthrough=1}}

File:Nine Elms Battersea regeneration site.jpg

In 2006, Irish property developers Real Estates Opportunities (REO) and Treasury Holdings purchased the Battersea Power Station site from Hong Kong property developer Parkview International for £400{{nbsp}}million.{{Cite news |date=30 November 2006 |title=Iconic landmark is sold for £400m |work=BBC News |url=http://news.bbc.co.uk/2/hi/uk_news/england/london/6160773.stm |access-date=9 September 2021 |archive-date=9 September 2021 |archive-url=https://web.archive.org/web/20210909142637/http://news.bbc.co.uk/2/hi/uk_news/england/london/6160773.stm |url-status=live }} In 2007, they abandoned the previously approved proposal for redeveloping the site, and appointed Rafael Viñoly to design a new masterplan for the site.{{Cite news |last=Westbrook |first=Andrew |date=5 April 2007 |title=Back To Square One For Power Station |url=http://www.wandsworthguardian.co.uk/news/topstories/display.var.1312060.0.back_to_square_one_for_power_station.php |archive-url=https://web.archive.org/web/20080526004550/http://www.wandsworthguardian.co.uk:80/news/topstories/display.var.1312060.0.back_to_square_one_for_power_station.php |archive-date=26 May 2008 |access-date=9 September 2021 |website=Wandsworth Guardian}} Transport consultants assessed what improvements to public transport were required to allow the site to be viably developed. Replacing the previously proposed plan to upgrade Battersea Park station at a cost of £26{{nbsp}}million,{{Cite web |date=28 February 2006 |title= £26m to be spend [sic] on Battersea Park station |url=http://icsouthlondon.icnetwork.co.uk/0100news/0550wandsworth/tm_objectid=16754466&method=full&siteid=50100&headline=-26m-to-be-spend-on-battersea-park-station-name_page.html |archive-url=https://web.archive.org/web/20060306065328/http://icsouthlondon.icnetwork.co.uk/0100news/0550wandsworth/tm_objectid=16754466&method=full&siteid=50100&headline=-26m-to-be-spend-on-battersea-park-station-name_page.html |archive-date=6 March 2006 |access-date=13 September 2021 |website=icSouthlondon |publisher= Trinity Mirror}} a privately funded extension of the Northern line was proposed to serve the Battersea Power Station site.{{Cite web |date=2010 |title=Battersea Power Station |url=http://www2.battersea-powerstation.com/ |archive-url=https://web.archive.org/web/20101127194322/http://www.battersea-powerstation.com/ |archive-date=27 November 2010 |access-date=9 September 2021 |publisher=Battersea Power Station |quote=Privately funded and subject to permissions, the new tube extension could be operating by 2016.}}{{Cite web |date=April 2013 |title=London Underground (Northern Line Extension) Order SUPPORTING STATEMENT |url=https://content.tfl.gov.uk/nle-twa-twa-supporting-statement-a6.pdf |url-status=live |access-date=9 September 2021 |publisher=Transport for London |pages=5–9 |archive-date=3 November 2021 |archive-url=https://web.archive.org/web/20211103021531/https://content.tfl.gov.uk/nle-twa-twa-supporting-statement-a6.pdf }}

In June 2008, REO and Treasury Holdings announced their plans for the site. Their masterplan proposed refurbishing the power station to include office and retail space, 3,200 new homes and a biomass power station. They announced that they were in discussions with Transport for London (TfL) regarding an extension of the Northern line to serve the site.{{Cite news |last=Booth |first=Robert |date=20 June 2008 |title=Latest plans for Battersea power station revealed |website=The Guardian |location=London |url=http://www.theguardian.com/artanddesign/2008/jun/20/art.architecture |url-status=live |access-date=9 September 2021 |archive-url=https://web.archive.org/web/20210909142641/https://www.theguardian.com/artanddesign/2008/jun/20/art.architecture |archive-date=9 September 2021 |quote=Now the developer is in talks with Transport for London about funding an extension of the Northern Line to the site at a cost of £346m. It would be largely funded by Treasury Holdings as part of any planning deal.}} The developer noted that Vauxhall is the closest Underground station to the site, and claimed that the station and the Victoria line were already at capacity.{{Cite press release |date=20 June 2008 |title=Battersea Power Station is Reborn |url=http://www.batterseapowerstation.org.uk/news/reo_20.06.08/reo_news_release_08.06.08.pdf |archive-url=https://web.archive.org/web/20090920105506/http://www.batterseapowerstation.org.uk/news/reo_20.06.08/reo_news_release_08.06.08.pdf |archive-date=20 September 2009 |access-date= 9 September 2021 |publisher= Battersea Power Station}}

In October 2008, the United States ambassador to the United Kingdom announced that the Embassy of the United States would move to a new site at Nine Elms, vacating its Mayfair location at Grosvenor Square.{{Cite news |last=Castle |first=Stephen |date=2 October 2008 |title=U.S. Embassy to relocate in London |work=The New York Times |url=https://www.nytimes.com/2008/10/02/world/europe/02iht-london.4.16652652.html |access-date=9 September 2021 |archive-date=9 September 2021 |archive-url=https://web.archive.org/web/20210909142637/https://www.nytimes.com/2008/10/02/world/europe/02iht-london.4.16652652.html |url-status=live }} Plans for the embassy were approved in 2009, with infrastructure contributions towards an extension of the Northern line.{{Cite news |date=2009-09-16 |title=Planners approve new US embassy |language=en-GB |work=BBC News |url=http://news.bbc.co.uk/2/hi/uk_news/england/london/8260096.stm |access-date=2023-02-15 |quote=The outline permission is subject to detailed negotiations on contributions to the cost of local and strategic transport improvements. This would include funding towards Crossrail or the council's preferred alternative of a Northern Line extension from Kennington.}}

In 2009, as part of the development of the Vauxhall Nine Elms Battersea Opportunity Area Planning Framework by the Greater London Authority (GLA), TfL considered the transport options for different amounts of development in the area. Options assessed by TfL included upgrading nearby stations, extending London Underground lines to the site, as well as improving local bus routes.{{Cite web |last=Thiagarajan |first=Suresh |date=16 October 2018 |title=Northern Line Extension Project |url=https://www.thepwi.org/technical_hub/presentations_for_tech_hub/181015_pwi_ueeiv_conference_manchester/09_suresh_thiagarajan |url-status=live |access-date=13 September 2021 |website=Permanent Way Institution |archive-date=27 July 2020 |archive-url=https://web.archive.org/web/20200727143337/https://www.thepwi.org/technical_hub/presentations_for_tech_hub/181015_pwi_ueeiv_conference_manchester/09_suresh_thiagarajan }} The report concluded that a high level of development in the area would require an extension of the Northern line to Battersea. In July 2009, TfL made clear that there was no funding available in its Business Plan for an extension, and that it would have to be privately funded.{{Cite web |last1=Tracey |first1=Richard |last2=Johnson |first2=Boris |date=6 July 2009 |title=Northern Line Extension |url=https://www.london.gov.uk/questions/2009/1999 |url-status=live |access-date=9 September 2021 |website=Mayor's Question Time |archive-date=9 September 2021 |archive-url=https://web.archive.org/web/20210909142659/https://www.london.gov.uk/questions/2009/1999 }}

In April 2010, London Mayor Boris Johnson published the Mayor's Transport Strategy (MTS), which outlined the Mayor's plans for public transport in the capital.{{Cite web |date=19 January 2015 |title=Mayor's Transport Strategy 2010 |url=https://www.london.gov.uk//what-we-do/transport/transport-publications/mayors-transport-strategy |url-status=live |archive-url=https://web.archive.org/web/20210430022032/https://www.london.gov.uk/what-we-do/transport/transport-publications/mayors-transport-strategy |archive-date=30 April 2021 |access-date=31 March 2021 |website=Greater London Authority |language=en-GB}} This specifically supported a privately funded extension of the Northern line to Battersea, to assist with regeneration of the Vauxhall, Nine Elms and Battersea areas.{{Cite web |date=May 2010 |title=Mayor's Transport Strategy – Chapter five – Transport proposals |url=https://www.london.gov.uk/sites/default/files/mts_chapter_5_pt1_0.pdf |url-status=live |archive-url=https://web.archive.org/web/20210817073212/https://www.london.gov.uk/sites/default/files/mts_chapter_5_pt1_0.pdf |archive-date=17 August 2021 |access-date=9 September 2021 |website=Greater London Authority |page=139}}

In May of that year, REO and Treasury Holdings launched a consultation into the extension of the Northern line to Battersea.{{Cite web|date=May 2010|title=Proposals for a Northern Line extension to Nine Elms and Battersea|url=http://www.dragondark.co.uk/lr/leafletcampaign.pdf|archive-url=https://web.archive.org/web/20170729231337/http://www.dragondark.co.uk/lr/leafletcampaign.pdf|archive-date=29 July 2017|access-date=9 September 2021|publisher=Real Estate Opportunities and Treasury Holdings}} As well as increasing the accessibility of their site, the developers noted that the extension would relieve Vauxhall station and serve redevelopment sites in the area including the new US Embassy and New Covent Garden Market. The consultation noted construction could be completed by 2016. Four options were included in the consultation, all extensions of the Northern line from Kennington to Battersea.

• Option 1 – no intermediate stations, providing the fastest journey time to Battersea with the lowest cost. However, the route would not serve Nine Elms or other areas.
• Option 2 – Battersea and a station in south Nine Elms, south of the South West Main Line (SWML). This would serve major development sites and existing residential areas.
• Option 3 – Battersea and an interchange station at Vauxhall station. This would have the highest cost due to complex engineering. Despite the benefit of connecting to the Victoria line and National Rail services at Vauxhall station, it was thought that the route might "exacerbate crowding issues" on the Victoria line and at Vauxhall station.
• Option 4 – Battersea and a station in north Nine Elms, north of the South West Main Line. Although located close to Vauxhall station and the new US Embassy, the route would not serve existing residential areas.

By November 2010, planning permission for the Battersea Power Station project had been granted by Wandsworth Council, with £203{{nbsp}}million pledged by the developers towards a future extension of the Northern line.{{cite press release|url=http://www.wandsworth.gov.uk/news/article/10136/battersea_power_station_scheme_approved|title=Battersea Power Station scheme approved|publisher=Wandsworth Council|date=11 November 2010|access-date=9 September 2021|archive-url=https://web.archive.org/web/20131014095827/http://www.wandsworth.gov.uk/news/article/10136/battersea_power_station_scheme_approved|archive-date=14 October 2013|quote=Before work begins Treasury Holdings will sign a legal agreement pledging more than £211m to improving local infrastructure and community services. Around £203m of this would go towards extending the Northern Line.}}{{Cite web |last=Kollewe |first=Julia |date=12 November 2010 |title=Battersea power station revamp gets go-ahead |url=http://www.theguardian.com/business/2010/nov/12/battersea-power-station-redevelopment-approved |url-status=live |archive-url=https://web.archive.org/web/20210909151133/https://www.theguardian.com/business/2010/nov/12/battersea-power-station-redevelopment-approved |archive-date=9 September 2021 |access-date=9 September 2021 |website=The Guardian |language=en}} At the end of the year, the scheme was approved by the Mayor of London.{{cite news|date=22 December 2010|title=Mayor approves £5.5bn Battersea Power Station revamp|work=BBC News|url=https://www.bbc.co.uk/news/uk-england-london-12063517|access-date=20 June 2018|archive-date=30 November 2017|archive-url=https://web.archive.org/web/20171130141134/http://www.bbc.co.uk/news/uk-england-london-12063517|url-status=live}}

Noting the difficult economic state of the UK due to the financial crisis, the GLA advised landowners, developers and local council leaders in November 2010 that the extension would be mostly privately funded via developers' contributions, costing the extension at £560{{nbsp}}million.{{cite press release|url=http://www.wandsworth.gov.uk/news/article/10120/study_shows_nine_elms_tube_link_viable|title=Study shows Nine Elms tube link viable|publisher=Wandsworth Council|date=5 November 2010|access-date=9 November 2010|archive-date=13 February 2011|archive-url=https://web.archive.org/web/20110213035716/http://www.wandsworth.gov.uk/news/article/10120/study_shows_nine_elms_tube_link_viable|url-status=live}}{{Cite web|date=September 2010|title=Northern Line Extension (NLE) Briefing Note 2 (September 2010)|url=http://www2.battersea-powerstation.com/pdfs/NLE_briefing_note_sept_2010.pdf|archive-url=https://web.archive.org/web/20110222012349/http://www2.battersea-powerstation.com/pdfs/NLE_briefing_note_sept_2010.pdf|archive-date=22 February 2011|access-date=9 September 2021|website=Battersea Power Station}} Options for funding the extension included direct developer contributions (such as from the Battersea Power Station developers), redirection of the Crossrail Mayoral Community Infrastructure Levy in the local area to the project, and Tax increment financing.{{cite news|date=29 October 2009|title=Boris: Nine Elms developers won't pay Crossrail levy|work=Architects' Journal|url=http://www.architectsjournal.co.uk/news/daily-news/boris-nine-elms-developers-wont-pay-crossrail-levy/5210159.article|access-date=5 January 2012|archive-date=6 November 2014|archive-url=https://web.archive.org/web/20141106172101/http://www.architectsjournal.co.uk/news/daily-news/boris-nine-elms-developers-wont-pay-crossrail-levy/5210159.article|url-status=live}}

File:London Underground Northern line extension map.svg

In May 2011, the preferred route of the extension was announced,{{Cite web|date=23 August 2011|title=Northern Line Extension to Nine Elms & Battersea – Home|url=http://northernlineextension.com/|archive-url=https://web.archive.org/web/20110823095911/http://northernlineextension.com/|archive-date=23 August 2011|access-date=9 September 2021|website=Northern Line Extension}} using the previously proposed Option 2 via Nine Elms.{{Cite web |date=May 2011 |title=Extension of the Northern line to Nine Elms and Battersea |url=http://northernlineextension.com/media/5087/nle_consultation_leaflet_d11_pages_lr.pdf |archive-url=https://web.archive.org/web/20110823101112/http://northernlineextension.com/media/5087/nle_consultation_leaflet_d11_pages_lr.pdf |archive-date=23 August 2011 |access-date=9 September 2021 |website=Northern Line Extension |quote=In stage 1 of the consultation, we were told that the route via south Nine Elms was the preferred option}} The Nine Elms station was proposed to be located adjacent to Wandsworth Road and a Sainsbury's supermarket, south of the South West Main Line viaduct. The Battersea station was proposed to be located to the south of the Battersea Power Station development site, adjacent to Battersea Park Road.{{Cite web |date=May 2011 |title=Extension of the Northern line to Nine Elms and Battersea |url=http://northernlineextension.com/media/5087/nle_consultation_leaflet_d11_pages_lr.pdf |archive-url=https://web.archive.org/web/20110823101112/http://northernlineextension.com/media/5087/nle_consultation_leaflet_d11_pages_lr.pdf |archive-date=23 August 2011 |access-date=2023-02-15 |website=Northern Line Extension |quote=Two ventilation shafts are also required: one in the vicinity of Kennington Green and one around Kennington Park.}}

Following criticism during the consultation by local residents that route options were not considered, the consultation was extended until August 2011 so that the public could comment on the previously proposed route options.{{Cite web|date=June 2011|title=Proposed Extension of the Northern line to Nine Elms and Battersea Public Consultation May–June 2011 – Update|url=http://northernlineextension.com/media/6789/nle_route_options_lr_pages.pdf|archive-url=https://web.archive.org/web/20110823101028/http://northernlineextension.com/media/6789/nle_route_options_lr_pages.pdf|archive-date=23 August 2011|access-date=9 September 2021|website=Northern Line Extension|quote=Route 2 is currently the preferred option because it offers the most benefits, however, no formal decision on this has yet been taken and your views will be considered}} However, Option 2 remained the preferred option. Following feedback during consultation, the project would ensure that a future extension to Clapham Junction station could be built in the future.{{Cite web|date=2012|title=Northern line extension Factsheet 8: Previous consultation on the Northern line extension (NLE) and our response to issues raised|url=https://consultations.tfl.gov.uk/tube/nle/supporting_documents/Factsheet8.pdf|url-status=live|access-date=9 September 2021|website=Transport for London|quote=Consultation responses raised some interest in the possibility of the Northern line being extended beyond Battersea as far as Clapham Junction. The proposals allow for the potential for a future extension beyond Battersea.|archive-date=9 September 2021|archive-url=https://web.archive.org/web/20210909230032/https://consultations.tfl.gov.uk/tube/nle/supporting_documents/Factsheet8.pdf}} The consultation noted that the extension could open by 2017, pending potential delays.{{Cite web |date=May 2011 |title=Extension of the Northern line to Nine Elms and Battersea |url=http://northernlineextension.com/media/5087/nle_consultation_leaflet_d11_pages_lr.pdf |archive-url=https://web.archive.org/web/20110823101112/http://northernlineextension.com/media/5087/nle_consultation_leaflet_d11_pages_lr.pdf |archive-date=23 August 2011 |access-date=2023-02-15 |website=Northern Line Extension |quote=This means that the new stations at Nine Elms and Battersea could be open in 2017.}}

In October 2011, a report commissioned by Wandsworth Borough Council showed that the proposed extension had a positive business case, with the potential of delivering up to £4.5{{nbsp}}billion in tax receipts across the area.{{Cite web|last=Rosewell|first=Bridget|date=October 2011|title=The Wider Economic Benefits of VNEB Regeneration - Interim Report|url=https://volterra.co.uk/wp-content/uploads/2013/02/NLE-Report-October-2011.pdf|url-status=live|access-date=10 September 2021|website=Volterra|archive-date=19 September 2021|archive-url=https://web.archive.org/web/20210919014545/https://volterra.co.uk/wp-content/uploads/2013/02/NLE-Report-October-2011.pdf}} In November 2011, Chancellor George Osborne announced that the UK Government would financially support the extension of the Northern line to Battersea, with the potential creation of an Enterprise Zone in the surrounding area.{{Cite news|date=29 November 2011|title=Northern Line: Government backs Tube extension plan|language=en-GB|work=BBC News|url=https://www.bbc.com/news/uk-england-london-15937031|access-date=9 September 2021|archive-date=9 September 2021|archive-url=https://web.archive.org/web/20210909142646/https://www.bbc.com/news/uk-england-london-15937031|url-status=live}}{{Cite web|last1=Odell|first1=Mark|last2=Pickford|first2=James|date=4 December 2012|title=Plan to break Battersea transport deadlock|url=https://www.ft.com/content/635051a8-3e3f-11e2-91cb-00144feabdc0|url-status=live|access-date=9 September 2021|website=Financial Times|archive-date=9 September 2021|archive-url=https://web.archive.org/web/20210909142640/https://www.ft.com/content/635051a8-3e3f-11e2-91cb-00144feabdc0}}

In December 2011, Treasury Holdings went into administration, after failing to repay debts of £340{{nbsp}}million to Lloyds Banking Group and Ireland's National Asset Management Agency (NAMA).{{Cite news |last=Kollewe |first=Julia |date=20 December 2011 |title=Irish property developers' grand vision for Battersea power station left in ruins |work=The Guardian |location=London |url=http://www.theguardian.com/business/2011/dec/20/irish-property-developers-battersea-power-station |url-status=live |access-date=9 September 2021 |archive-url=https://web.archive.org/web/20211027191514/https://www.theguardian.com/business/2011/dec/20/irish-property-developers-battersea-power-station |archive-date=27 October 2021}}{{Cite news |last1=O'Carroll |first1=Lisa |last2=Moya |first2=Elena |date=21 December 2010 |title=Ireland's 'bad bank' NAMA becomes one of world's biggest property lenders |work=The Guardian |location=London |url=http://www.theguardian.com/business/2010/dec/20/ireland-nama-banks-property-loans |url-status=live |access-date=9 September 2021 |archive-url=https://web.archive.org/web/20210415143335/https://www.theguardian.com/business/2010/dec/20/ireland-nama-banks-property-loans |archive-date=15 April 2021}} Due to the financial crisis and the collapse of the Irish property bubble, REO and Treasury Holdings had not been able to find an investor to allow them to proceed with the development. REO had been criticised by investors and potential partners for their high levels of debt, as well as their "overly litigious" approach to business. For the first time in its history, the power station site was put up for sale on the open market. As part of the sale, the £200{{nbsp}}million contribution to the Northern line extension remained, as well as the approved planning permission.{{Cite news |last1=Prynn |first1=Jonathan |last2=Cecil |first2=Nicholas |last3=Bar-Hillel |first3=Mira |date=10 April 2012 |title=New Sale: Battersea power station |url=https://www.standard.co.uk/news/london/new-sale-battersea-power-station-7496801.html |url-status=live |access-date=9 September 2021 |website=Evening Standard |location=London |archive-date=9 September 2021 |archive-url=https://web.archive.org/web/20210909142647/https://www.standard.co.uk/news/london/new-sale-battersea-power-station-7496801.html }} Despite the sale of the site, Mayor Boris Johnson requested that the planning and development of the extension continue, with responsibility of the project passing to TfL.

In March 2012, the Vauxhall Nine Elms Battersea Opportunity Area Planning Framework was published by the GLA, proposing 16,000 new homes, {{convert|500000|sqm}} of commercial space and 27,000 new jobs across the area, as well as outlining the infrastructure requirements required to support this level of growth.{{Cite web |date=March 2021 |title=Vauxhall Nine Elms Battersea Opportunity Area Planning Framework |publisher= Greater London Authority |url=http://www.london.gov.uk/who-runs-london/mayor/publications/planning/vauxhall-nine-elms-battersea-opportunity-area-planning-framework |archive-url=https://web.archive.org/web/20120816012504/http://www.london.gov.uk/who-runs-london/mayor/publications/planning/vauxhall-nine-elms-battersea-opportunity-area-planning-framework |archive-date=16 August 2012 |access-date=9 September 2021}}

File:Nine Elms Sainsburys (London, UK).JPG

In June 2012, the Battersea Power Station site was sold to a Malaysian consortium of companies for £400{{nbsp}}million. The consortium included S P Setia (a property company), Sime Darby (a trading conglomerate) and Employees Provident Fund (Malaysia's largest pension fund).{{cite news |title=Battersea Power Station: Malaysian company beats Chelsea bid |url=https://www.bbc.co.uk/news/uk-england-london-18352786 |work=BBC News |date=7 June 2012 |access-date=7 June 2012 |archive-date=7 June 2012 |archive-url=https://web.archive.org/web/20120607101333/http://www.bbc.co.uk/news/uk-england-london-18352786 |url-status=live }}{{Cite web|last1=Hammond|first1=Ed|last2=Grant|first2=Jeremy|date=5 July 2012|title=Malaysians seal £400m Battersea deal|url=https://www.ft.com/content/0b13b6b2-c674-11e1-963a-00144feabdc0|url-status=live|access-date=14 September 2021|website=Financial Times|archive-date=14 September 2021|archive-url=https://web.archive.org/web/20210914105820/https://www.ft.com/content/0b13b6b2-c674-11e1-963a-00144feabdc0}} The consortium stated that they were in favour of the extension, and confirmed that they would honour the £200{{nbsp}}million contribution towards the extension.{{Cite news|last=Werdigier|first=Julia|date=7 June 2012|title=New Buyers for Venerable London Power Station|language=en-US|work=The New York Times|url=https://www.nytimes.com/2012/06/08/business/global/2-malaysian-property-groups-to-buy-bankrupt-london-landmark.html|access-date=9 September 2021|issn=0362-4331|archive-date=9 September 2021|archive-url=https://web.archive.org/web/20210909144052/https://www.nytimes.com/2012/06/08/business/global/2-malaysian-property-groups-to-buy-bankrupt-london-landmark.html|url-status=live}}{{Cite web|last1=Kenyon|first1=Peter|last2=McInnes|first2=Ian|date=July 2012|title=Northern Line extension gains momentum|url=https://www.tunneltalk.com/London-Underground-Jul12-Northern-Line-extension-to-Battersea-gains-momentum.php|url-status=live|access-date=10 September 2021|website=Tunnel Talk|archive-date=10 September 2021|archive-url=https://web.archive.org/web/20210910103516/https://www.tunneltalk.com/London-Underground-Jul12-Northern-Line-extension-to-Battersea-gains-momentum.php}}

In November 2012, TfL launched a consultation into the preferred route, before seeking permission for the extension to be built.{{cite press release|title=TfL would like to hear your views on plans to extend the Northern line|url=https://tfl.gov.uk/info-for/media/press-releases/2012/november/tfl-would-like-to-hear-your-views-on-plans-to-extend-the-northern-line|publisher=Transport for London|date=8 November 2012|access-date=9 September 2021|archive-date=9 September 2021|archive-url=https://web.archive.org/web/20210909230032/https://tfl.gov.uk/info-for/media/press-releases/2012/november/tfl-would-like-to-hear-your-views-on-plans-to-extend-the-northern-line|url-status=live}}{{Cite news|date=15 November 2012|title=Northern Line extension consultation begins|language=en-GB|work=BBC News|url=https://www.bbc.com/news/uk-england-london-20336676|access-date=10 September 2021|archive-date=10 September 2021|archive-url=https://web.archive.org/web/20210910103511/https://www.bbc.com/news/uk-england-london-20336676|url-status=live}} TfL had reassessed the various route options and the potential station sites at both Battersea and Nine Elms.{{Cite web |date=2012 |title=Northern line extension Factsheet 8: Previous consultation on the Northern line extension (NLE) and our response to issues raised |url=https://consultations.tfl.gov.uk/tube/nle/supporting_documents/Factsheet8.pdf |url-status=live |archive-url=https://web.archive.org/web/20210909230032/https://consultations.tfl.gov.uk/tube/nle/supporting_documents/Factsheet8.pdf |archive-date=9 September 2021 |access-date=9 September 2021 |website=Transport for London |quote=Some concerns were raised about the first phase of public consultation conducted in summer 2010. ... Following public consultation in summer 2011, TfL undertook a detailed assessment of the various route options. This concluded that route 2 was the best option to take forward.}} Residents were also concerned regarding the potential levels of overcrowding at Kennington station, and TfL were considering if works were required to mitigate this.{{Cite web|last1=Johnson|first1=Boris|last2=Shawcross|first2=Valerie|date=31 May 2012|title=Kennington station|url=https://www.london.gov.uk/questions/2012/1615|url-status=live|access-date=11 September 2021|website=Mayor's Question Time|archive-date=11 September 2021|archive-url=https://web.archive.org/web/20210911182000/https://www.london.gov.uk/questions/2012/1615}} The proposed station site at Battersea was vacant, and the proposed station site at Nine Elms was being used as a supermarket car park, as well as an office building.{{Cite web|last=Dixon|first=J S|date=19 June 2014|title=Report to the Secretary of State for Transport and the Secretary of State for Communities and Local Government – Transport and Works Act 1992 Town and Country Planning Act 1990 Planning (Listed Buildings and Conservation Areas) Act 1990 and Acquisition of Land Act 1981 – London Underground (Northern Line Extension) Order 201[ ]|url=https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/737161/northern-line-inspectors-report.pdf|url-status=live|access-date=13 September 2021|website=HM Government|pages=7–8|archive-date=2 December 2021|archive-url=https://web.archive.org/web/20211202014657/https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/737161/northern-line-inspectors-report.pdf}} This helped ensure that local opposition to demolition (such as the London Astoria for the Crossrail project) was avoided.

Funding for the extension was agreed with HM Treasury in 2012, with the use of tax increment financing and financial contributions by developers to pay back the construction loan over a period of 25 years.

File:Kennington front 2020.jpg, where the extension splits from the existing Northern line]]

In April 2013, TfL applied for a Transport and Works Act Order to seek permission to build the extension.{{cite news |url=http://www.railwaygazette.com/news/projects-infrastructure/single-view/view/tfl-applies-for-northern-line-extension-legal-powers.html |title= TfL applies for Northern Line extension legal powers |work= Railway Gazette International |location= London |date= 30 April 2013 |access-date= 3 May 2013 |archive-date= 19 June 2013 |archive-url=https://web.archive.org/web/20130619183619/http://www.railwaygazette.com/news/projects-infrastructure/single-view/view/tfl-applies-for-northern-line-extension-legal-powers.html |url-status= live }} TfL also began work to appoint a contractor to build the extension, as well as undertaking ground investigation works to understand the soil and subsoil where the new tunnels are to be built.{{Cite web|last=Pitt|first=Vern|date=3 July 2013|title=Four teams in for £600m Battersea Northern Line extension|url=https://www.building.co.uk/news/four-teams-in-for-600m-battersea-northern-line-extension/5057248.article|url-status=live|access-date=11 September 2021|website=Building magazine|archive-date=11 September 2021|archive-url=https://web.archive.org/web/20210911111955/https://www.building.co.uk/news/four-teams-in-for-600m-battersea-northern-line-extension/5057248.article}} That summer, Prime Minister David Cameron and Prime Minister of Malaysia Najib Razak broke ground on the £8{{nbsp}}billion Battersea Power Station development, with Cameron stating that "where once there was little hope of decent public transport links, we have nailed that problem".{{Cite web|last=Cameron|first=David|date=4 July 2013|title=David Cameron: Battersea is a symbol of Britain's renewal|url=https://www.standard.co.uk/comment/comment/david-cameron-battersea-is-a-symbol-of-britain-s-renewal-8687882.html|url-status=live|access-date=13 September 2021|website=Evening Standard|language=en|quote=Where once there was little hope of decent public transport links, we have nailed that problem with the Northern line extension. This needed a financial guarantee from Government to get going: we provided it, now it's happening.|archive-date=13 September 2021|archive-url=https://web.archive.org/web/20210913214647/https://www.standard.co.uk/comment/comment/david-cameron-battersea-is-a-symbol-of-britain-s-renewal-8687882.html}}{{Cite news|date=4 July 2013|title=Battersea Power Station work opened by David Cameron and Malaysian PM|language=en-GB|work=BBC News|url=https://www.bbc.com/news/uk-england-london-23177197|access-date=13 September 2021|archive-date=28 January 2016|archive-url=https://web.archive.org/web/20160128172606/http://www.bbc.com/news/uk-england-london-23177197|url-status=live}}

On 19 November 2013, the Secretary of State for Transport announced the start of a public inquiry to be conducted by an independent planning inspector, into the proposed construction of the extension.{{cite press release|title=Northern line extension public inquiry starts today|url=https://tfl.gov.uk/info-for/media/press-releases/2013/november/northern-line-extension-public-inquiry-starts-today|publisher=Transport for London|date=19 November 2013|access-date=11 September 2021|archive-date=11 September 2021|archive-url=https://web.archive.org/web/20210911111953/https://tfl.gov.uk/info-for/media/press-releases/2013/november/northern-line-extension-public-inquiry-starts-today|url-status=live}}{{Cite web|last=Rucki|first=Alexandra|date=19 November 2013|title=Public inquiry launches into Northern Line extension to Battersea|url=https://www.yourlocalguardian.co.uk/news/10818512.public-inquiry-launches-into-northern-line-extension-to-battersea/|url-status=live|access-date=11 September 2021|website=Your Local Guardian|language=en|archive-date=11 September 2021|archive-url=https://web.archive.org/web/20210911111955/https://www.yourlocalguardian.co.uk/news/10818512.public-inquiry-launches-into-northern-line-extension-to-battersea/}} During the inquiry, the inspector heard from those in favour of the extension (such as TfL, the promoter of the extension, as well as other supporters), from those objecting to the extension, as well as points raised by concerned third parties (such as from statutory undertakers).

Points covered in the inquiry included that the extension would only serve one developer, that other alternatives (such as a route via Vauxhall) were not sufficiently tested, impacts on local Conservation Areas and Kennington Park, that an extension to Clapham Junction station should be built, as well as concerns regarding the levels of noise, vibration and dust during construction.{{Cite web |last=Dixon |first=J S |date=19 June 2014 |title=Report to the Secretary of State for Transport and the Secretary of State for Communities and Local Government – Transport and Works Act 1992 Town and Country Planning Act 1990 Planning (Listed Buildings and Conservation Areas) Act 1990 and Acquisition of Land Act 1981 – London Underground (Northern Line Extension) Order 201[ ] |url=https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/737161/northern-line-inspectors-report.pdf |archive-url=https://web.archive.org/web/20211202014657/https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/737161/northern-line-inspectors-report.pdf |archive-date=2 December 2021 |access-date=11 September 2021 |website=HM Government |page=12}} The inspector noted that the support of the extension by the three local London boroughs "should not be underestimated", and that there was "strong support from businesses and interests" across the Vauxhall Nine Elms Battersea Opportunity Area and the wider area.{{Cite web |last=Dixon |first=J S |date=19 June 2014 |title=Report to the Secretary of State for Transport and the Secretary of State for Communities and Local Government – Transport and Works Act 1992 Town and Country Planning Act 1990 Planning (Listed Buildings and Conservation Areas) Act 1990 and Acquisition of Land Act 1981 – London Underground (Northern Line Extension) Order 201[ ] |url=https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/737161/northern-line-inspectors-report.pdf |archive-url=https://web.archive.org/web/20211202014657/https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/737161/northern-line-inspectors-report.pdf |archive-date=2 December 2021 |access-date=11 September 2021 |website=HM Government |pages=12–13}} TfL's responsiveness was also recognised, acting upon feedback to modifying the scheme to limit concerns, as well as adopting the most "stringent operational noise controls than on any other new underground railway in the UK".

The public inquiry was completed on 20 December 2013.{{Cite web |last=Dixon |first=J S |date=19 June 2014 |title=Report to the Secretary of State for Transport and the Secretary of State for Communities and Local Government – Transport and Works Act 1992 Town and Country Planning Act 1990 Planning (Listed Buildings and Conservation Areas) Act 1990 and Acquisition of Land Act 1981 – London Underground (Northern Line Extension) Order 201[ ] |url=https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/737161/northern-line-inspectors-report.pdf |archive-url=https://web.archive.org/web/20211202014657/https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/737161/northern-line-inspectors-report.pdf |archive-date=2 December 2021 |access-date=11 September 2021 |website=HM Government |pages=i–ii}} In June 2014, the planning inspector recommended that the scheme proceed along with various recommendations. The extension was given the final approval by Secretary of State for Transport Patrick McLoughlin in November 2014, and was projected to open in 2020 at a cost of around £1{{nbsp}}billion.{{cite news|last=de Peyer|first=Robin|date=12 November 2014|title=Northern Line extension to Battersea and Nine Elms gets go ahead|work=Evening Standard|url=https://www.standard.co.uk/news/transport/northern-line-extension-to-battersea-and-nine-elms-approved-by-government-lambeth-9856878.html|access-date=12 November 2014|archive-date=12 November 2014|archive-url=https://web.archive.org/web/20141112214508/http://www.standard.co.uk/news/transport/northern-line-extension-to-battersea-and-nine-elms-approved-by-government-lambeth-9856878.html|url-status=live}}{{Cite news|date=12 November 2014|title=Northern Line extension to Battersea and Nine Elms given go-ahead|language=en-GB|work=BBC News|url=https://www.bbc.com/news/uk-england-london-30032017|access-date=11 September 2021|archive-date=27 August 2021|archive-url=https://web.archive.org/web/20210827002532/https://www.bbc.com/news/uk-england-london-30032017|url-status=live}}

File:Northern Line Extension..jpg

File:Battersea Power station development September 2017 - 23744721648.jpg

In August 2014, Mike Brown, managing director of London Underground, announced that a £500{{nbsp}}million six-year contract had been awarded to a joint venture of Ferrovial Agroman and Laing O'Rourke{{Cite web |date=9 September 2014 |title=Ferrovial consortium chosen to expand London Underground for 628 million euro |url=https://newsroom.ferrovial.com/en/press_releases/london-underground-northern-line-extension/ |url-status=live |archive-url=https://web.archive.org/web/20210911181951/https://newsroom.ferrovial.com/en/press_releases/london-underground-northern-line-extension/ |archive-date=11 September 2021 |access-date=11 September 2021 |website=Ferrovial |language=en}} to design and build the Northern line extension to Battersea, with Mott MacDonald as design engineer.{{Cite web|date=21 August 2014|title=Northern Line extension contractor selected|url=https://www.railwaygazette.com/northern-line-extension-contractor-selected/39873.article|url-status=live|access-date=11 September 2021|website=Railway Gazette International|language=en|archive-date=11 September 2021|archive-url=https://web.archive.org/web/20210911111955/https://www.railwaygazette.com/northern-line-extension-contractor-selected/39873.article}} Awaiting the final approval, TfL noted that the project could be completed before the Crossrail project, pending any potential delays.{{Cite web|date=21 May 2014|title=Northern Line extension could open before Crossrail|url=https://railuk.com/rail-news/northern-line-extension-could-open-before-crossrail/|access-date=11 September 2021|website=Rail UK|language=en-US|archive-date=11 September 2021|archive-url=https://web.archive.org/web/20210911111956/https://railuk.com/rail-news/northern-line-extension-could-open-before-crossrail/|url-status=live}}

Preparation works started on the route in 2015, with Mayor Boris Johnson officially starting construction on 23 November 2015 at a ceremony at Battersea Power Station.{{Cite web|date=25 November 2015|title=Northern Line extension breaks ground|url=https://www.railwaygazette.com/northern-line-extension-breaks-ground/41687.article|url-status=live|access-date=11 September 2021|website=Railway Gazette International|language=en|archive-date=11 September 2021|archive-url=https://web.archive.org/web/20210911111955/https://www.railwaygazette.com/northern-line-extension-breaks-ground/41687.article}}{{Cite web|last=Shenouda|first=Josh|date=25 November 2015|title=Boris Johnson starts work on the Northern line extension to Battersea and Nine Elms|url=https://www.wandsworthguardian.co.uk/news/14102999.boris-johnson-starts-work-on-the-northern-line-extension-to-battersea-and-nine-elms/|url-status=live|access-date=11 September 2021|website=Wandsworth Times|language=en|archive-date=11 September 2021|archive-url=https://web.archive.org/web/20210911224001/https://www.wandsworthguardian.co.uk/news/14102999.boris-johnson-starts-work-on-the-northern-line-extension-to-battersea-and-nine-elms/}} Boring of the tunnels was estimated to begin in 2017, with the extension complete by 2020.

In mid-February 2017, two large tunnel boring machines were delivered to the Battersea construction site, and lowered to tunnel level by a large crane.{{Cite web|date=20 January 2017|title=London Underground Northern Line extension tunnelling to start in March|url=https://www.railwaygazette.com/infrastructure/london-underground-northern-line-extension-tunnelling-to-start-in-march/43855.article|url-status=live|access-date=11 September 2021|website=Railway Gazette International|language=en|archive-date=11 September 2021|archive-url=https://web.archive.org/web/20210911111958/https://www.railwaygazette.com/infrastructure/london-underground-northern-line-extension-tunnelling-to-start-in-march/43855.article}} The boring machines were named Helen and Amy – after the first British astronaut Helen Sharman, and Amy Johnson, the first female pilot to fly solo from London to Australia – following a competition amongst local school children.{{Cite web |last=Murray |first=Dick |date=16 February 2017 |title=Machines brought in to begin work on £1.2bn Northern line extension |url=https://www.standard.co.uk/news/transport/northern-line-extension-machines-lowered-into-place-to-begin-work-on-ps1-2bn-tube-extension-a3468121.html |url-status=live |archive-url=https://web.archive.org/web/20210911213131/https://www.standard.co.uk/news/transport/northern-line-extension-machines-lowered-into-place-to-begin-work-on-ps1-2bn-tube-extension-a3468121.html |archive-date=11 September 2021 |access-date=11 September 2021 |website=Evening Standard |language=en |quote=They were named, thanks to a vote by local schoolchildren, in honour of astronaut Helen Sharman and aviation pioneer Amy Johnson}} A {{convert|300|m|adj=on|abbr=in}} temporary conveyor belt was constructed to transport an estimated 300,000{{nbsp}}tonnes of excavated material from the Battersea construction site to the River Thames, where it would loaded onto barges to be transported to East Tilbury to create new arable farmland.{{Cite web|date=20 January 2017|title=Tilbury set to get new farm land thanks to project to extend London's Underground service|url=https://www.thurrockgazette.co.uk/news/15038030.tilbury-set-to-get-new-farm-land-thanks-to-project-to-extend-londons-underground-service/|url-status=live|access-date=11 September 2021|website=Thurrock Gazette|language=en|archive-date=11 September 2021|archive-url=https://web.archive.org/web/20210911111956/https://www.thurrockgazette.co.uk/news/15038030.tilbury-set-to-get-new-farm-land-thanks-to-project-to-extend-londons-underground-service/}}{{Cite magazine|last=Kitching|first=Ruby|date=17 March 2017|title=Tunnelling {{!}} Northern Line extension|url=https://www.newcivilengineer.com/archive/tunnelling-northern-line-extension-17-03-2017/|access-date=11 September 2021|magazine=New Civil Engineer|language=en|archive-date=11 September 2021|archive-url=https://web.archive.org/web/20210911111955/https://www.newcivilengineer.com/archive/tunnelling-northern-line-extension-17-03-2017/|url-status=live}}

The main tunnelling work started in April 2017{{cite web |url=https://tfl.gov.uk/info-for/media/press-releases/2017/april/tunnelling-starts-to-extend-the-northern-line-to-battersea |title=Tunnelling starts to extend the Northern line to Battersea |publisher=Transport for London |date=11 April 2017 |access-date=29 March 2020 |archive-date=29 March 2020 |archive-url=https://web.archive.org/web/20200329215547/https://tfl.gov.uk/info-for/media/press-releases/2017/april/tunnelling-starts-to-extend-the-northern-line-to-battersea |url-status=live }} and was completed on 8 November 2017, with a breakthrough at Kennington.{{cite web|last=Collier|first=Hatty|date=8 November 2017|title=Northern Line extension: Tunnelling work on £1.2bn extension to Battersea completed ahead of 2020 opening|url=https://www.standard.co.uk/news/transport/northern-line-extension-tunnelling-work-on-12bn-extension-to-battersea-completed-ahead-of-2020-a3685746.html|url-status=live|access-date=11 September 2021|website=Evening Standard|archive-date=9 November 2020|archive-url=https://web.archive.org/web/20201109041335/https://www.standard.co.uk/news/transport/northern-line-extension-tunnelling-work-on-12bn-extension-to-battersea-completed-ahead-of-2020-a3685746.html}} Tunnelling work to connect the bored tunnels to the existing Kennington loop of the Northern line was dug by hand, due to risk of impacting the existing Northern line.{{Cite web|last=Kitching|first=Ruby|date=25 May 2017|title=Tunnelling: Northern link|url=https://www.geplus.co.uk/news/tunnelling-northern-link-25-05-2017/|access-date=13 September 2021|website=Ground Engineering|language=en|archive-date=13 September 2021|archive-url=https://web.archive.org/web/20210913212544/https://www.geplus.co.uk/news/tunnelling-northern-link-25-05-2017/|url-status=live}} Following the completion of tunnelling, work began on the installation of rails, power and communication equipment, as well as the station structures themselves.

In July 2017, Wandsworth Borough Council agreed to a request by the developers of Battersea Power Station to reduce the percentage of affordable housing at the development from 15% to 9%, due to the cost of the £266.4{{nbsp}}million contribution towards the extension.{{Cite news|last=Cuffe|first=Grainne|date=11 July 2017|title=Mayor of London brands Wandsworth Council 'shameful' for decision on affordable homes at Battersea Power Station|work=Wandsworth Times|url=https://www.wandsworthguardian.co.uk/news/15403420.mayor-of-london-sadiq-khan-brands-wandsworth-council-shameful-for-decision-on-affordable-homes-at-battersea-power-station/|url-status=live|access-date=11 September 2021|archive-date=11 September 2021|archive-url=https://web.archive.org/web/20210911110957/https://www.wandsworthguardian.co.uk/news/15403420.mayor-of-london-sadiq-khan-brands-wandsworth-council-shameful-for-decision-on-affordable-homes-at-battersea-power-station/}} This was criticised by the Mayor of London, Sadiq Khan, who called the request to reduce the affordable housing 'shameful'.

In December 2017, the detailed designs for Battersea station were approved by Wandsworth Council.{{Cite web|date=21 December 2017|title=Historic day for east Battersea as design for new Northern Line tube station is given green light|url=https://www.wandsworth.gov.uk/news/article/14299|url-status=live|access-date=11 September 2021|website=Wandsworth Borough Council|language=en-gb|archive-date=11 September 2021|archive-url=https://web.archive.org/web/20210911111955/https://www.wandsworth.gov.uk/news/article/14299}} In January 2018, the first train travelled over the completed 'step plate' junctions at Kennington that will allow access to the extension.{{Cite web|last=Carr|first=Collin|date=9 January 2018|title=First train travels over new Northern line extension junction|url=https://railuk.com/rail-news/first-train-travels-over-new-northern-line-extension-junction/|access-date=11 September 2021|website=Rail UK|language=en-US|archive-date=11 September 2021|archive-url=https://web.archive.org/web/20210911111955/https://railuk.com/rail-news/first-train-travels-over-new-northern-line-extension-junction/|url-status=live}} In March 2018, the detailed designs for Nine Elms station were approved by Lambeth Council.{{Cite web|date=March 2018|title=18/00043/DET {{!}} Approval of details to discharge Condition 3(a) (i) (Stations and other buildings: detailed design approval of above ground elements) of the deemed planning permission for the London Underground Northern Line Extension (Nine Elms Station) (Ref : TWA 3/1/415) {{!}} Nine Elms TFL Construction Site, Pascal Street London SW8|url=https://planning.lambeth.gov.uk/online-applications/applicationDetails.do?activeTab=summary&keyVal=P21HDCBOKC900|url-status=live|access-date=14 September 2021|website=planning.lambeth.gov.uk|quote=Decision Issued Date Mon 05 Mar 2018|archive-date=21 January 2022|archive-url=https://web.archive.org/web/20220121222012/https://planning.lambeth.gov.uk/online-applications/applicationDetails.do?activeTab=summary&keyVal=P21HDCBOKC900}} In May 2018, Mayor of London Sadiq Khan noted that changes to the design of the development above the future Battersea station by the Power Station developer had increased the cost of the station by around £240{{nbsp}}million, and that TfL was seeking to recoup these costs.{{Cite web|last1=Khan|first1=Sadiq|last2=Eshalomi|first2=Florence|date=4 May 2018|title=Developer Funded Transport|url=https://www.london.gov.uk/questions/2018/1196|url-status=live|access-date=14 September 2021|website=Mayor's Question Time|quote=The additional costs to the Northern line extensions have been caused by significant changes made by the Battersea Power Station developer to the design of the development above the station at Battersea. More ambitious structures than were originally agreed have meant substantial changes are needed for the new Tube station to function properly. This had led to an increase in the overall cost of the project. TfL is in discussions with Battersea Power Station developers to recover these additional costs.|archive-date=17 October 2021|archive-url=https://web.archive.org/web/20211017055919/https://www.london.gov.uk/questions/2018/1196}} Work at Kennington to build additional platform cross passages was completed in September 2018.{{Cite news|date=2 October 2018|title=Finished complex cross passage works at Kennington Station in NLE|url=https://newsroom.ferrovial.com/en/local-news/northern-line-extension-team-delivers-complex-cross-passage-works-at-kennington-station-on-schedule/|url-status=live|access-date=11 September 2021|website=Ferrovial|language=en|archive-date=11 September 2021|archive-url=https://web.archive.org/web/20210911222459/https://newsroom.ferrovial.com/en/local-news/northern-line-extension-team-delivers-complex-cross-passage-works-at-kennington-station-on-schedule/}}File:Nine Elms station, April 2019.jpg

In January 2019, it was announced that due to a variety of construction delays, the opening of the project would be delayed from December 2020 to 2021.{{Cite web|last1=Plimmer|first1=Gill|last2=Pickard|first2=Jim|date=21 December 2018|title=London's Northern Line extension to Battersea delayed by a year|url=https://www.ft.com/content/7ac0080a-0455-11e9-99df-6183d3002ee1|url-status=live|access-date=11 September 2021|website=Financial Times|archive-date=11 September 2021|archive-url=https://web.archive.org/web/20210911182004/https://www.ft.com/content/7ac0080a-0455-11e9-99df-6183d3002ee1}}{{Cite news |last1=Prynn |first1=Jonathan |last2=Sleigh |first2=Sophia |date=21 December 2018 |title=TfL under fire as Battersea Tube extension is delayed by 'miscalculations' |work=Evening Standard |location=London |url=https://www.standard.co.uk/news/transport/tfl-under-fire-as-battersea-tube-extension-is-delayed-by-miscalculations-a4023386.html |url-status=live |access-date=8 May 2020 |archive-url=https://web.archive.org/web/20201023202028/https://www.standard.co.uk/news/transport/tfl-under-fire-as-battersea-tube-extension-is-delayed-by-miscalculations-a4023386.html |archive-date=23 October 2020}} In June 2019, it was announced that installation of track had been completed, and that an engineering train travelled the full length of the tunnel from Kennington to Battersea for the first time.{{Cite web|date=18 June 2019|title=First engineering train travels full Northern Line Extension|url=https://www.railwaypro.com/wp/first-engineering-train-travels-full-northern-line-extension/|access-date=11 September 2021|website=Railway PRO|language=en-US|archive-date=11 September 2021|archive-url=https://web.archive.org/web/20210911114956/https://www.railwaypro.com/wp/first-engineering-train-travels-full-northern-line-extension/|url-status=live}}{{Cite web|last=|date=14 June 2019|title=Northern Line extension due to open in September 2021 as trackwork completed|url=https://www.railwaygazette.com/infrastructure/northern-line-extension-due-to-open-in-september-2021-as-trackwork-completed/48721.article|url-status=live|access-date=11 September 2021|website=Railway Gazette International|language=en|archive-date=11 September 2021|archive-url=https://web.archive.org/web/20210911111955/https://www.railwaygazette.com/infrastructure/northern-line-extension-due-to-open-in-september-2021-as-trackwork-completed/48721.article}} By February 2020, construction of the extension was nearly complete, with platforms, escalators and the Tube Roundel installed in the stations.{{Cite web |last=Jarvis |first=Jacob |date=20 February 2020 |title=Battersea Power Station signs unveiled at new Northern Line hub |url=https://www.standard.co.uk/news/transport/battersea-power-station-tube-signs-unveiled-underground-northern-line-a4367426.html |url-status=live |archive-url=https://web.archive.org/web/20200221144206/https://www.standard.co.uk/news/transport/battersea-power-station-tube-signs-unveiled-underground-northern-line-a4367426.html |archive-date=21 February 2020 |access-date=13 April 2020 |website=Evening Standard}} In the early spring of 2020, work on the extension was paused due to the COVID-19 pandemic. Work resumed at the end of May 2020 with social distancing and other mitigation measures.{{Cite web|last1=Eshalomi|first1=Florence|last2=Khan|first2=Sadiq|date=7 September 2020|title=Update on the Northern Line Extension|url=https://www.london.gov.uk/questions/2020/3133|url-status=live|access-date=11 September 2021|website=Mayor's Question Time|archive-date=11 September 2021|archive-url=https://web.archive.org/web/20210911182009/https://www.london.gov.uk/questions/2020/3133}} In July 2020, the roof of the Battersea station was handed over to the Battersea Power Station developer to allow their construction to begin. In late 2020, stations were energised and track traction current turned on.{{Cite magazine |last=Horgan |first=Rob |date=4 Jan 2021 |title=Northern Line Extension on track for 2021 opening as train testing begins |url=https://www.newcivilengineer.com/latest/northern-line-extension-on-track-for-2021-opening-as-train-testing-begins-04-01-2021/ |url-access=subscription |url-status=live |archive-url=https://web.archive.org/web/20210910223313/https://nineelmslondon.com/transformation/northern-line-extension/ |archive-date=10 September 2021 |access-date=11 September 2021 |magazine=New Civil Engineer |language=en-US |quote=Several major construction milestones on the project were ticked off last year, including: Switching on a permanent electricity supply to the new Tube stations at Battersea Power Station and Nine Elms Energising the traction power supply to the rails, enabling passenger trains to run along the new tracks}} Subsequently, the first 1995 Stock train ran onto the extension over the 2020 Christmas period, marking the start of the signal testing period.{{Cite press release|title=First passenger trains complete journeys on new Northern Line Extension|url=https://tfl.gov.uk/info-for/media/press-releases/2021/january/first-passenger-trains-complete-journeys-on-new-northern-line-extension|access-date=4 January 2021|website=Transport for London|archive-date=4 January 2021|archive-url=https://web.archive.org/web/20210104095157/https://tfl.gov.uk/info-for/media/press-releases/2021/january/first-passenger-trains-complete-journeys-on-new-northern-line-extension|url-status=live}}

Kennington station was moved from Zone 2 to the Zone 1/2 boundary in May 2021, in preparation for the opening of the extension.{{Cite web|last=Bennett|first=Ella|date=13 May 2021|title=Kennington on the Northern Line line is changing zones as lockdown eases|url=https://www.mylondon.news/news/south-london-news/london-underground-northern-line-station-20588563|access-date=11 September 2021|website=MyLondon|language=en|archive-date=11 September 2021|archive-url=https://web.archive.org/web/20210911181947/https://www.mylondon.news/news/south-london-news/london-underground-northern-line-station-20588563|url-status=live}} In June 2021, it was announced that the extension would have 4G mobile signal, unlike the majority of the tunnelled Underground network in 2021.{{Cite web|last=Lydall|first=Ross|date=22 June 2021|title=Tube to get full mobile phone coverage by 2024|url=https://www.standard.co.uk/news/london/london-underground-full-mobile-phone-coverage-2024-b941881.html|url-status=live|access-date=11 September 2021|website=Evening Standard|language=en|archive-date=11 September 2021|archive-url=https://web.archive.org/web/20210911230734/https://www.standard.co.uk/news/london/london-underground-full-mobile-phone-coverage-2024-b941881.html}} By summer 2021, final testing and commissioning was underway, with regular test trains running from July 2021.{{Cite web|last=White|first=Chloe|date=11 July 2021|title=Transport for London Northern Line Extension project meets a major milestone as trial operations begin|url=https://www.railadvent.co.uk/2021/07/transport-for-london-northern-line-extension-project-meets-a-major-milestone-as-trial-operations-begin.html|url-status=live|access-date=11 July 2021|website=RailAdvent|language=en-GB|archive-date=11 July 2021|archive-url=https://web.archive.org/web/20210711130949/https://www.railadvent.co.uk/2021/07/transport-for-london-northern-line-extension-project-meets-a-major-milestone-as-trial-operations-begin.html}}

File:Battersea Power Station Station (51496672361).jpg

The extension was opened on 20 September 2021,{{Cite news |date=20 September 2021 |title=Northern line extension: Two new Tube stations open |work=BBC News |url=https://www.bbc.com/news/uk-england-london-58621491 |url-status=live |access-date=20 September 2021 |archive-url=https://web.archive.org/web/20210920073208/https://www.bbc.com/news/uk-england-london-58621491 |archive-date=20 September 2021}}{{Cite news |date=20 September 2021 |title=London Underground's first major expansion this century opens |url=https://www.itv.com/news/london/2021-09-20/london-undergrounds-first-major-expansion-this-century-opens |access-date=20 September 2021 |website=ITV News |archive-date=20 September 2021 |archive-url=https://web.archive.org/web/20210920225206/https://www.itv.com/news/london/2021-09-20/london-undergrounds-first-major-expansion-this-century-opens |url-status=live }} the first major extension of the Underground since the Jubilee Line Extension in 1999.{{Cite news |date=20 August 2021 |title=Battersea boost imminent |website=Modern Railways |url=https://www.keymodernrailways.com/article/battersea-boost-imminent |url-status=live |access-date=11 September 2021 |archive-url=https://web.archive.org/web/20210911222510/https://www.keymodernrailways.com/article/battersea-boost-imminent |archive-date=11 September 2021 |quote=the first major new stretch of tube railway since the Jubilee Line extension (JLE) opened at the turn of the millennium.}} The initial peak-time service was six trains per hour, with five trains an hour at off-peak times.{{Cite press release |date=16 September 2021 |title=New Tube map unveiled featuring new Northern line stations to open next week as Tube extends to Battersea Power Station |url=https://tfl.gov.uk/info-for/media/press-releases/2021/september/new-tube-map-unveiled-featuring-new-northern-line-stations-to-open-next-week-as-tube-extends-to-battersea-power-station |url-status=live |access-date=16 September 2021 |publisher=Transport for London |archive-date=16 September 2021 |archive-url=https://web.archive.org/web/20210916085356/https://tfl.gov.uk/info-for/media/press-releases/2021/september/new-tube-map-unveiled-featuring-new-northern-line-stations-to-open-next-week-as-tube-extends-to-battersea-power-station}} The new stations were criticised by disability campaigners, with Alan Benson criticising lifts for being too small and like a "squeezed-in afterthought”.{{Cite web |last=Talora |first=Joe |date=2021-09-28 |title=Northern Line extension described as 'missed opportunity' for accessible transport after teething problems |url=https://www.standard.co.uk/news/london/northern-line-extension-nine-elms-battersea-tfl-accesibility-b957706.html |access-date=27 June 2024 |website=Evening Standard |language=en}} London Assembly Member Siân Berry called the failings "disappointing", and disability charity Scope called the project a "missed opportunity". TfL apologised, stating that they were taking feedback onboard and making changes.

In June 2022, service levels were doubled, following completion of works relating to the Bank station upgrade.{{Cite web |last=Lydall |first=Ross |date=2022-09-23 |title=Five million trips on Northern line extension |url=https://www.standard.co.uk/news/transport/five-million-trips-on-northern-line-extension-b1027717.html |url-status=live |archive-url=https://web.archive.org/web/20220927110612/https://www.standard.co.uk/news/transport/five-million-trips-on-northern-line-extension-b1027717.html |archive-date=27 September 2022 |access-date=2022-09-27 |website=Evening Standard |language=en |quote=The number of trains on the route was doubled in June, from six to 12 trains per hour during peak times, and from five to 10 trains per hour off-peak.}}{{Cite magazine |last=Smith |first=Claire |date=3 September 2021 |title=TfL's Northern Line Extension opening date revealed |url=https://www.newcivilengineer.com/latest/tfls-northern-line-extension-opening-date-revealed-03-09-2021/ |url-status=live |archive-url=https://web.archive.org/web/20220121221959/https://www.newcivilengineer.com/latest/tfls-northern-line-extension-opening-date-revealed-03-09-2021/ |archive-date=21 January 2022 |access-date=14 September 2021 |magazine=New Civil Engineer |quote=At the time, TfL said that introduction of services on the new line is being "realigned" to coincide with the opening of the Bank Station upgrade allowing for additional capacity on the line. Nonetheless, the impact of Covid and other project issues mean that the upgrade will now not be completed until at least mid-2022 with a blockade on the line planned at Bank between January and May 2022.}} In September 2022, TfL announced that over 5{{nbsp}}million trips had been made on the extension since opening, with an average of 40,000 trips a week at Nine Elms and 80,000 at Battersea Power Station.{{Cite web |last=Lydall |first=Ross |date=2022-09-23 |title=Five million trips on Northern line extension |url=https://www.standard.co.uk/news/transport/five-million-trips-on-northern-line-extension-b1027717.html |url-status=live |archive-url=https://web.archive.org/web/20220927110612/https://www.standard.co.uk/news/transport/five-million-trips-on-northern-line-extension-b1027717.html |archive-date=27 September 2022 |access-date=2022-09-27 |website=Evening Standard |language=en}} Battersea Power Station noted that demand would increase further from October 2022, with the opening of the Power Station as an office and retail complex. TfL estimate that demand could increase to 10 million a year by 2024{{ndash}}25.{{Cite web |last= |first= |date=23 September 2022 |title=Over five million journeys made on the Northern Line Extension in its first year |url=https://tfl.gov.uk/info-for/media/press-releases/2022/september/over-five-million-journeys-made-on-the-northern-line-extension-in-its-first-year |access-date=2022-09-27 |website=Transport for London |language=en-GB |archive-date=27 September 2022 |archive-url=https://web.archive.org/web/20220927110612/https://tfl.gov.uk/info-for/media/press-releases/2022/september/over-five-million-journeys-made-on-the-northern-line-extension-in-its-first-year |url-status=live }}

In November 2022, Battersea Power Station was awarded the Architects' Journal Architecture Award for Infrastructure and Transport, with praise for the quality of the architecture on the extension overall.{{Cite web |last=Williams |first=Fran |date=2022-11-23 |title=AJ Architecture Awards 2022 winners revealed |url=https://www.architectsjournal.co.uk/news/aj-architecture-awards-2022-winners-revealed |access-date=2023-08-19 |website=The Architects’ Journal |language=en}}

{{Northern line extension to Battersea}}

The Northern line extension consists of two new parallel tunnels ({{cvt|3150|m}} long northbound and {{cvt|3250|m}} long southbound), two new stations, and two ventilation shafts. Both stations are fully accessible with step-free access from street to train,{{Cite web |date=2012 |title=Northern Line Extension Proposed route and key sites |url=https://content.tfl.gov.uk/nle-map.pdf |archive-url=https://web.archive.org/web/20211103021034/https://content.tfl.gov.uk/nle-map.pdf |archive-date=3 November 2021 |access-date=10 September 2021 |website=Transport for London}} and are located in Zone 1.{{Cite press release |date=13 May 2021 |title=Zone 1 confirmed for new Battersea and Nine Elms Tube stations |url=https://www.wandsworth.gov.uk/news/news-may-2021/zone-1-confirmed-for-new-battersea-and-nine-elms-tube-stations/ |url-status=live |access-date=11 September 2021 |publisher=Wandsworth Borough Council |archive-date=11 September 2021 |archive-url=https://web.archive.org/web/20210911182714/https://www.wandsworth.gov.uk/news/news-may-2021/zone-1-confirmed-for-new-battersea-and-nine-elms-tube-stations/}} Neither station on the extension has platform-edge doors installed, although provision has been made for future installation should they be required.{{Cite web |last=Pidgeon |first=Caroline |date=10 June 2019 |title=Platform edge doors on the Northern Line |url=https://www.london.gov.uk/questions/2019/11986 |url-status=live |archive-url=https://web.archive.org/web/20210914112229/https://www.london.gov.uk/questions/2019/11986 |archive-date=14 September 2021 |access-date=14 September 2021 |website=Mayor's Question Time}}

Branching off the Northern line at Kennington, the tunnels connect to the Kennington Loop, a loop of tunnel that allows Northern line trains from the Charing Cross branch of the line to turn around. Although the loop remains, the two tunnels branch off it to head south. Two shafts at Kennington Park and Kennington Green provide ventilation and emergency access to the tunnels. Passing underneath Oval tube station and the Victoria line tunnels, the line turns west.

Nine Elms station is located adjacent to Wandsworth Road, and is the only intermediate station on the route.{{Cite web|date=September 2013|title=Factsheet E: New station at Nine Elms|url=https://content.tfl.gov.uk/nl-factsheet-e-web.pdf|url-status=live|access-date=10 September 2021|website=Transport for London|archive-date=10 September 2021|archive-url=https://web.archive.org/web/20210910222953/https://content.tfl.gov.uk/nl-factsheet-e-web.pdf}} A pedestrian route under the Nine Elms to Waterloo Viaduct allows access to the US Embassy and other developments in Nine Elms.{{Cite web|date=9 February 2021|title=New connections: Arch 42|url=https://nineelmslondon.com/features/arch42/|url-status=live|access-date=10 September 2021|website=Nine Elms on the South Bank|language=en-US|archive-date=10 September 2021|archive-url=https://web.archive.org/web/20210910222954/https://nineelmslondon.com/features/arch42/}} The line continues, slowly turning towards the south to become parallel with Battersea Park Road.

Battersea Power Station station is located at the south of the Battersea Power Station development site, a short walk from Battersea Park station.{{Cite web|date=September 2013|title=Factsheet M: New station at Battersea|url=https://content.tfl.gov.uk/nl-factsheet-m-web.pdf|url-status=live|access-date=10 September 2021|website=Transport for London|archive-date=3 November 2021|archive-url=https://web.archive.org/web/20211103021026/https://content.tfl.gov.uk/nl-factsheet-m-web.pdf}} A crossover junction prior to the station allows trains to terminate in either platform. Overrun tunnels underneath Battersea Dogs & Cats Home were proposed, however these were omitted to save money.{{Cite web |date=20 August 2021 |title=Battersea boost imminent |url=https://www.modernrailways.com/article/battersea-boost-imminent |url-status=live |archive-url=https://web.archive.org/web/20220810091425/https://www.modernrailways.com/article/battersea-boost-imminent |archive-date=10 August 2022 |access-date=2022-08-10 |website=Modern Railways |language=en |quote=This prompted a descoping of the tunnels beyond Battersea Power Station to become short 20-metre overrun tunnels, with trains to be outstabled in the platforms at Nine Elms and Battersea Power Station instead.}}

File:Sunset, Sunrise, Sunset by Alexandre da Cunha.jpg]]

The station buildings at Nine Elms and Battersea Power Station and other structures such as the ventilation head houses in Kennington were designed by Grimshaw Architects.{{Cite press release |date=21 December 2017 |title=Battersea Station receives planning approval |url=https://grimshaw.global/news/articles/battersea-station-receives-planning-approval/ |url-status=live |access-date=11 September 2021 |publisher=Grimshaw Architects |archive-date=21 January 2022 |archive-url=https://web.archive.org/web/20220121222015/https://grimshaw.global/news/articles/battersea-station-receives-planning-approval/ }}{{Cite tweet |user=GrimshawArch |date=20 September 2021 |title=The Northern Line Extension was opened by Sadiq Khan @MayorofLondon today. Our designs include two new underground stations at #BatterseaPowerStation and #NineElms, two new ventilation shaft head houses at Kennington and new cross passages at Kennington Station. |number=1439960884701454337 |author= Grimshaw Architects }} Both stations were built using the cut-and-cover station box method, where the station is built in a large concrete box dug out of the ground.{{Cite news |last=Lydall |first=Ross |date=21 May 2021 |title=First extension to London Underground this century to open in Sept |url=https://www.standard.co.uk/news/london/northern-line-extension-nine-elms-battersea-open-september-b936566.html |url-status=live |access-date=12 September 2021 |work=Evening Standard |location=London |archive-date=26 September 2021 |archive-url=https://web.archive.org/web/20210926040425/https://www.standard.co.uk/news/london/northern-line-extension-nine-elms-battersea-open-september-b936566.html }}

At Nine Elms, the station was constructed to have a future residential development of 479 new homes designed by Assael Architecture built above the station.{{Cite magazine |last=Lowe |first=Tom |date=23 April 2021 |title=Assael clears planning for £144m scheme above Nine Elms tube station |url=https://www.bdonline.co.uk/news/assael-clears-planning-for-144m-scheme-above-nine-elms-tube-station/5111527.article |url-status=live |magazine=Building Design |location=London |access-date=11 September 2021 |archive-date=21 January 2022 |archive-url=https://web.archive.org/web/20220121222023/https://www.bdonline.co.uk/news/assael-clears-planning-for-144m-scheme-above-nine-elms-tube-station/5111527.article }} This development will be a joint venture between property developer Grainger plc and TfL's property development company Places for London.{{Cite web |title=Nine Elms |url=https://www.connectedlivinglondon.co.uk/nine-elms/ |access-date=2025-02-28 |website=Connected Living London |language=en-GB}}

Both stations on the extension were to have permanent artworks installed by TfL's contemporary art programme, Art on the Underground.{{Cite news |last=Krause |first=Riley |date=9 September 2019 |title=Here are the artworks that will decorate Battersea and Nine Elms Northern Line stations |url=https://www.wandsworthguardian.co.uk/news/17890892.artworks-will-decorate-battersea-nine-elms-northern-line-stations/ |url-status=live |access-date=11 September 2021 |website=Wandsworth Times |archive-date=21 January 2022 |archive-url=https://web.archive.org/web/20220121222001/https://www.wandsworthguardian.co.uk/news/17890892.artworks-will-decorate-battersea-nine-elms-northern-line-stations/ }}{{Cite press release |date=6 September 2019 |title= Artworks announced for Battersea and Nine Elms Northern Line stations |url=https://www.wandsworth.gov.uk/news/september-2019/artworks-announced-for-battersea-and-nine-elms-northern-line-stations/ |archive-url=https://web.archive.org/web/20200920070442/https://wandsworth.gov.uk/news/september-2019/artworks-announced-for-battersea-and-nine-elms-northern-line-stations/ |archive-date=20 September 2020 |access-date=13 April 2020 |publisher= Wandsworth Borough Council}} At Battersea Power Station, Brazilian-British artist Alexandre da Cunha installed Sunset, Sunrise, Sunset, a {{convert|100|m|sing=on}} kinetic sculpture in the ticket hall of the station, using the obsolete technology of the rotating billboard.{{Cite web |title=Sunset, Sunrise, Sunset |url=https://art.tfl.gov.uk/projects/sunset-sunrise-sunset/ |access-date=13 April 2020 |website=Art on the Underground |archive-date=16 June 2020 |archive-url=https://web.archive.org/web/20200616175917/https://art.tfl.gov.uk/projects/sunset-sunrise-sunset/ |url-status=live }}{{Cite press release |title= Artworks announced for Battersea and Nine Elms Northern Line stations |url=https://www.wandsworth.gov.uk/news/september-2019/artworks-announced-for-battersea-and-nine-elms-northern-line-stations/ |access-date=13 April 2020 |publisher= Wandsworth Borough Council |archive-url=https://web.archive.org/web/20200920070442/https://wandsworth.gov.uk/news/september-2019/artworks-announced-for-battersea-and-nine-elms-northern-line-stations/ |archive-date=20 September 2020 |date=6 September 2019}} The proposed artwork for Nine Elms was not installed for technical reasons, and a new work will be commissioned in the future.{{Cite tweet |author= Art on the Underground |user=aotulondon |date=3 September 2021 |title=The artwork at Nine Elms as originally conceived by artist Samara Scott will not be able to go ahead for technical reasons. Details of a commission for a permanent artwork at this station will be announced in due course. |website=Twitter |number=1433830211842347008}} During the period of construction, Art on the Underground commissioned two artists, Emma Smith and Nina Wakeford, to undertake temporary artworks, engaging with local residents, construction workers and TfL staff to create them.{{Cite web |last=Thurloway |first=Jameela |date=24 April 2019 |title=Emma Smith |url=https://www.contemporaryartsociety.org/news/artist-to-watch/emma-smith/ |url-status=live |archive-url=https://web.archive.org/web/20210914101406/https://www.contemporaryartsociety.org/news/artist-to-watch/emma-smith/ |archive-date=14 September 2021 |access-date=14 September 2021 |website=Contemporary Art Society |quote=In 2017 Smith produced Televox, the first commission by Art on the Underground's artist‐led engagement programme, which focuses on communities working and living along the Northern Line Extension (due for completion in 2020).}}{{Cite web |date=26 November 2019 |title=Nina Wakeford's Art on the Underground commission celebrates London communities past, present and future |url=https://www.rca.ac.uk/news-and-events/news/nina-wakefords-art-underground-commission-celebrates-london-communities-past-present-and-future/ |url-status=live |archive-url=https://web.archive.org/web/20210914101406/https://www.rca.ac.uk/news-and-events/news/nina-wakefords-art-underground-commission-celebrates-london-communities-past-present-and-future/ |archive-date=14 September 2021 |access-date=14 September 2021 |website=Royal College of Art |location=London}} In October 2023, Labyrinth artworks by artist Mark Wallinger were installed at both Battersea Power station and Nine Elms, marking 10 years of the artworks and the 160th anniversary of the London Underground.{{Cite web |last=Lawrence |first=India |date=2023-10-20 |title=Two more tube stations now have these iconic maze designs |url=https://www.timeout.com/london/news/two-more-tube-stations-now-have-these-iconic-maze-designs-102023 |access-date=2023-10-21 |website=Time Out London |language=en-GB}}

File:Battersea Power station redevelopment Dec 2020.jpg

The construction of the extension was supported by local boroughs, property developers with redevelopment sites in the area,{{Cite press release |date=3 September 2021 |title=Battersea Power Station Underground To Open |url=https://batterseapowerstation.co.uk/news/article/battersea-power-station-underground-to-open-september-nle |url-status=live |access-date=11 September 2021 |publisher=Battersea Power Station |archive-date=21 January 2022 |archive-url=https://web.archive.org/web/20220121222008/https://batterseapowerstation.co.uk/news/article/battersea-power-station-underground-to-open-september-nle}} as well as local people living near the extension.{{Cite news |last=Meyer |first=James |date=10 September 2021 |title=Two new tube stations to open (this is what residents think of them) |website=Wandsworth Times |url=https://www.wandsworthguardian.co.uk/news/19572747.new-northern-line-tube-stations-battersea-power-station-nine-elms/ |url-status=live |access-date=11 September 2021 |archive-url=https://web.archive.org/web/20210911182004/https://www.wandsworthguardian.co.uk/news/19572747.new-northern-line-tube-stations-battersea-power-station-nine-elms/ |archive-date=11 September 2021}}{{Cite news |date=24 May 2021 |title=Northern line extension to open in months to support London's Covid recovery |work=Metro |location=London |url=https://metro.co.uk/2021/05/24/northern-line-extension-to-open-in-months-to-support-covid-recovery-14624771/ |url-status=live |access-date=11 September 2021 |archive-url=https://web.archive.org/web/20210911181947/https://metro.co.uk/2021/05/24/northern-line-extension-to-open-in-months-to-support-covid-recovery-14624771/ |archive-date=11 September 2021 |quote=During the consultation, the vast majority of respondents supported the plans, with 87% agreeing it would benefit the area.}} Lambeth and Wandsworth Councils have estimated that around 20,000 new homes and 25,000 new jobs could be provided, and that the extension will support the "regeneration of the Vauxhall Nine Elms Battersea area".{{Cite web |date=23 August 2011 |title=Northern Line Extension to Nine Elms & Battersea – Key Benefits |url=http://northernlineextension.com/key-benefits.aspx |archive-url=https://web.archive.org/web/20110823100024/http://northernlineextension.com/key-benefits.aspx |archive-date=23 August 2011 |access-date=9 September 2021 |website=Northern Line Extension}} Developers and local councils noted that access to major development sites across the area such as Battersea Power Station, Embassy Gardens, New Covent Garden Market and the US Embassy will be improved by the extension, especially that the extension is in Zone 1.

As with the proposed Bakerloo line extension, TfL proposes to use its property development arm to build residential development above Nine Elms station and at a Kennington worksite following the opening of the extension. This would recoup some of the costs of building the extension, as well as providing long term income for TfL.{{Cite web |title=Property Development |url=https://www.tfl.gov.uk/info-for/business-and-commercial/property-development |archive-url=https://web.archive.org/web/20210309142656/https://tfl.gov.uk/info-for/business-and-commercial/property-development |archive-date=9 March 2021 |access-date=2 April 2021 |publisher=Transport for London |quote=Our landholdings can play a vital role in meeting the Mayor's priorities to build affordable homes, while generating revenue to invest in improving our transport network.}}

Transport in the local area has been improved, bringing rapid transit to communities currently served only by buses, as well as the more frequent trains than existing National Rail services from Battersea Park station. In 2022, TfL noted that journey times from the area to the City and the West End have been cut by 50%, with an average journey time saving of 17 minutes. Furthermore, TfL state that the extension will reduce overcrowding on local bus services and at Vauxhall station, as well as on the Victoria and Northern lines.{{Cite web |title=Northern line extension – Benefits of the NLE |url=https://tfl.gov.uk/travel-information/improvements-and-projects/northern-line-extension |archive-url=https://web.archive.org/web/20210126164047/https://tfl.gov.uk/travel-information/improvements-and-projects/northern-line-extension |archive-date=26 January 2021 |access-date=26 February 2023 |publisher=Transport for London}} The extension has also increased the number of accessible, step-free Underground stations.

The Vauxhall Nine Elms Battersea regeneration also improved other transport infrastructure in the area, including cycle lanes, a new Thames Clippers river boat pier and an upgrade of Vauxhall Underground station at a cost of £36{{nbsp}}million providing step-free access to the Victoria line.{{Cite web |date= 20 May 2013 |title= Vauxhall Tube upgrade begins next year |url=https://nineelmslondon.com/news/vauxhall-tube-upgrade-begins-next-year/ |url-status= live |access-date= 12 September 2021 |website= Nine Elms on the South Bank |archive-date= 12 September 2021 |archive-url=https://web.archive.org/web/20210912112102/https://nineelmslondon.com/news/vauxhall-tube-upgrade-begins-next-year/ }}{{Cite web|title=Battersea Power Station Pier – Uber Boat by Thames Clippers|url=https://www.thamesclippers.com/plan-your-journey/find-your-pier/battersea-power-station-pier|url-status=live|access-date=13 September 2021|website=Thames Clippers|archive-date=14 April 2021|archive-url=https://web.archive.org/web/20210414221356/https://www.thamesclippers.com/plan-your-journey/find-your-pier/battersea-power-station-pier}} Other proposed works have included a new bridge across the River Thames to Pimlico and a planned rebuild of Vauxhall bus station.{{Cite magazine |last=Clark |first=Tim |date=17 December 2020 |title=Nine Elms bridge scheme 'paused' after Covid forces council rethink |url=https://www.architectsjournal.co.uk/news/controversial-nine-elms-footbridge-on-indefinite-hold |access-date=13 September 2021 |magazine=The Architects' Journal |location=London |archive-date=9 February 2021 |archive-url=https://web.archive.org/web/20210209121956/https://www.architectsjournal.co.uk/news/controversial-nine-elms-footbridge-on-indefinite-hold |url-status=live }}

File:Embassy Gardens SW8 - 40041212911.jpg development adjacent to Nine Elms station]]

However, the extension has been criticised for a variety of reasons. The percentage of affordable housing at the Battersea Power Station development was reduced in 2017, partially due to the cost of the £266.4{{nbsp}}million contribution towards the extension, drawing scorn from affordable housing advocates.{{Cite news |date=2 February 2021 |title=Penthouses and poor doors: how Europe's 'biggest regeneration project' fell flat |first=Oliver |last=Wainwright |url=http://www.theguardian.com/artanddesign/2021/feb/02/penthouses-poor-doors-nine-elms-battersea-london-luxury-housing-development |access-date=11 September 2021 |work=The Guardian |location=London |archive-date=21 September 2021 |archive-url=https://web.archive.org/web/20210921053009/https://www.theguardian.com/artanddesign/2021/feb/02/penthouses-poor-doors-nine-elms-battersea-london-luxury-housing-development |url-status=live }} Other commentary has critiqued the developments in the area catalysed by the extension, with concerns regarding high amount of foreign ownership and buy to let property investments, as opposed to local people purchasing properties.{{Cite web|last=Kollewe|first=Julia|date=14 February 2015|title=Battersea is part of a huge building project – but not for Londoners|url=http://www.theguardian.com/business/2015/feb/14/battersea-nine-elms-property-development-housing|url-status=live|access-date=13 September 2021|website=The Guardian|language=en|archive-date=21 January 2022|archive-url=https://web.archive.org/web/20220121222000/https://www.theguardian.com/business/2015/feb/14/battersea-nine-elms-property-development-housing}}

During the public inquiry, the planned extension was also criticised for a perception of an "extension for developers" and that money would have been better spent on other transport projects in London.{{Cite web |last=Dixon |first=J S |date=19 June 2014 |title=Report to the Secretary of State for Transport and the Secretary of State for Communities and Local Government – Transport and Works Act 1992 Town and Country Planning Act 1990 Planning (Listed Buildings and Conservation Areas) Act 1990 and Acquisition of Land Act 1981 – London Underground (Northern Line Extension) Order 201[ ] |url=https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/737161/northern-line-inspectors-report.pdf |archive-url=https://web.archive.org/web/20190729234913/https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/737161/northern-line-inspectors-report.pdf |archive-date=29 July 2019 |access-date=11 September 2014 |publisher=HM Government |page=180}} The potential of gentrification in the Vauxhall, Nine Elms and Battersea areas due to the extension was also noted. The extension has also been criticised for failing to extend to Clapham Junction railway station, one of the busiest stations in the UK, and the busiest station in London not currently on the Underground.{{Cite web |last=Dixon |first=J S |date=19 June 2014 |title=Report to the Secretary of State for Transport and the Secretary of State for Communities and Local Government – Transport and Works Act 1992 Town and Country Planning Act 1990 Planning (Listed Buildings and Conservation Areas) Act 1990 and Acquisition of Land Act 1981 – London Underground (Northern Line Extension) Order 201[ ] |url=https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/737161/northern-line-inspectors-report.pdf |archive-url=https://web.archive.org/web/20211202014657/https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/737161/northern-line-inspectors-report.pdf |archive-date=2 December 2021 |access-date=11 September 2021 |publisher=HM Government |pages=186–187}}

The extension is estimated to have cost around £1.1{{nbsp}}billion to construct. This amount is £160{{nbsp}}million below budget, despite construction delays. The extension was funded by a £1{{nbsp}}billion loan to the Greater London Authority from the Public Works Loan Board.{{cite news |last=Murphy |first=Joe |date=5 December 2012 |title=Boost for Battersea as Osborne puts power station on the Tube |work=Evening Standard |url=https://www.standard.co.uk/news/uk/boost-for-battersea-as-osborne-puts-power-station-on-the-tube-8386471.html?origin=internalSearch |url-status=live |access-date=19 January 2013 |archive-url=https://web.archive.org/web/20141006105720/http://www.standard.co.uk/news/uk/boost-for-battersea-as-osborne-puts-power-station-on-the-tube-8386471.html?origin=internalSearch |archive-date=6 October 2014}} For the first time in England, tax increment financing will be used to pay back £660m of the loan, using future business rates from the development in the Vauxhall Nine Elms Battersea area, over a period of 25 years.{{Cite news |last=Pickford |first=James |date=2013-04-08 |title=London project to use risky funding model |work=Financial Times |url=https://www.ft.com/content/fcda4910-9f64-11e2-b4b6-00144feabdc0 |access-date=2023-02-26}}{{Cite journal |last=Findeisen |first=Francesco |date=2022-07-04 |title=Financing the Northern Line Extension: the politics of governing Greater London |journal=Territory, Politics, Governance |volume=10 |issue=4 |pages=608–627 |doi=10.1080/21622671.2020.1782257 |s2cid=225543918 |issn=2162-2671}} Another £270m will be repaid by developer contributions (Section 106 agreements and Community Infrastructure Levy) in the area.{{Cite web|last1=Eshalomi|first1=Florence|last2=Khan|first2=Sadiq|date=10 June 2019|title=Northern Line Extension (1)|url=https://www.london.gov.uk/questions/2019/12202|url-status=live|access-date=11 September 2021|website=Mayor's Question Time|archive-date=11 September 2021|archive-url=https://web.archive.org/web/20210911181958/https://www.london.gov.uk/questions/2019/12202}}

File:450010 and 378224 at Clapham Junction.jpg]]

Provision has been made for a future extension of the Northern line to Clapham Junction station, with a reserved course underneath Battersea Park.{{cite news |last=Henderson |first=Jamie |date=23 June 2013 |title=Clapham Junction next for Northern Line says London Assembly member |newspaper=Wandsworth Guardian |url=http://www.wandsworthguardian.co.uk/news/10501385.Clapham_Junction_next_for_Northern_Line_says_London_Assembly_member/ |url-status=live |access-date=12 January 2014 |archive-url=https://web.archive.org/web/20131224115148/http://www.wandsworthguardian.co.uk/news/10501385.Clapham_Junction_next_for_Northern_Line_says_London_Assembly_member/ |archive-date=24 December 2013 |quote=A path running beneath Battersea Park has already been reserved for such a move}}{{Cite web|last1=Johnson|first1=Boris|last2=Darren|first2=Johnson|date=8 October 2012|title=Extension of Northern Line to Clapham Junction|url=https://www.london.gov.uk/questions/2012/2896|url-status=live|access-date=11 September 2021|website=Mayor's Question Time|quote=There are no current plans to extend further to Clapham Junction; however it is a requirement that the extension be designed so that a further extension would be possible in the future.|archive-date=11 September 2021|archive-url=https://web.archive.org/web/20210911182014/https://www.london.gov.uk/questions/2012/2896}} During the public inquiry into the extension in 2014, the inspector noted that although an extension to Clapham Junction would be desirable, it was unnecessary to meet the needs of the Vauxhall Nine Elms Battersea regeneration area. Additionally, it was noted that an extension to Clapham Junction could overwhelm the extension, due to the high demand.{{Cite web|last=Lydall|first=Ross|date=21 May 2021|title=First extension to London Underground this century to open in Sept|url=https://www.standard.co.uk/news/london/northern-line-extension-nine-elms-battersea-open-september-b936566.html|url-status=live|access-date=12 September 2021|website=Evening Standard|language=en|quote=Engineers have previously said that extending the Northern line to Clapham Junction could have overwhelmed the new route due.|archive-date=26 September 2021|archive-url=https://web.archive.org/web/20210926040425/https://www.standard.co.uk/news/london/northern-line-extension-nine-elms-battersea-open-september-b936566.html}}

As part of consultations into Crossrail 2 in 2014, the developer of the Battersea Power Station site suggested that Battersea could be the location of a station instead of at King's Road Chelsea. This would provide a link between the area and Clapham Junction station.{{Cite web |last=Beard |first=Matthew |date=11 August 2014 |title=Battersea Power Station owner makes bid for new Crossrail 2 station |url=https://www.standard.co.uk/news/transport/battersea-power-station-owner-makes-bid-for-new-crossrail-2-station-9661562.html |url-status=live |archive-url=https://web.archive.org/web/20210911111955/https://www.standard.co.uk/news/transport/battersea-power-station-owner-makes-bid-for-new-crossrail-2-station-9661562.html |archive-date=11 September 2021 |access-date=11 September 2021 |website=Evening Standard |language=en}} Despite the proposal for the future Crossrail 2 project to serve the station,{{Cite web|title=Clapham Junction|url=https://crossrail2.co.uk/stations/clapham-junction/|access-date=12 September 2021|website=Crossrail 2|archive-date=12 September 2021|archive-url=https://web.archive.org/web/20210912114830/https://crossrail2.co.uk/stations/clapham-junction/|url-status=live}} local residents and politicians have continued to request a future extension of the Northern line to Clapham Junction.{{Cite web |last=Chantler-Hicks |first=Lydia |date=2023-01-31 |title=Council looks at extension of Northern line to Clapham Junction |url=https://www.standard.co.uk/news/london/london-underground-northern-line-clapham-junction-wandsworth-borough-council-b1056869.html |access-date=2023-03-01 |website=Evening Standard |language=en}}{{Cite web |last=Lillywhite |first=Charlotte |date=2024-11-20 |title=Boost for Northern Line extension plans in south London |url=https://www.standard.co.uk/news/transport/northern-line-extension-no-restriction-to-linking-up-line-with-clapham-junction-terminus-b1195067.html |access-date=2024-11-22 |website=The Standard |language=en}} In March 2023, Mayor of London Sadiq Khan stated that the "case for an extension is not readily apparent, given Clapham Junction’s existing high levels of connectivity".{{Cite web |last=Khan |first=Sadiq |author-link=Sadiq Khan |last2=Cooper |first2=Leonie |author-link2=Leonie Cooper |date=10 March 2023 |title=Questions To The Mayor - Tube Extension |url=https://www.london.gov.uk/who-we-are/what-london-assembly-does/questions-mayor/find-an-answer/tube-extension-0 |access-date=22 November 2024 |website=Greater London Authority}}

In November 2024, Wandsworth Council announced that an initial feasibility study of an extension to Clapham Junction had been completed, and that there were "no physical engineering or geological constraints that would prevent the tube being extended". It was previously estimated that an extension would cost at least £750m.

Unlike other London Underground lines, the Northern line has two separate branches (Charing Cross and City) through Central London, meeting at Camden Town and Kennington.{{Cite web|last=Lawrence-Jones|first=Charlie|date=21 February 2020|title=Why the London Underground's Northern line has two branches|url=https://www.mylondon.news/news/zone-1-news/london-undergrounds-northern-line-two-17765529|access-date=13 September 2021|website=MyLondon|language=en|archive-date=13 September 2021|archive-url=https://web.archive.org/web/20210913212543/https://www.mylondon.news/news/zone-1-news/london-undergrounds-northern-line-two-17765529|url-status=live}} TfL has previously proposed splitting the line into two separate lines, with one line running from Edgware to Battersea Power Station via Charing Cross; and the other one running from High Barnet and Mill Hill East to Morden via Bank. This would allow more trains to run on each branch, increasing capacity by around 25%. The extension to Battersea now allows trains on the Charing Cross branch to terminate at Battersea Power Station.

However, a complete split into two lines would require Camden Town station to be rebuilt – given that the station is already severely overcrowded at peak times, and such a split would mean more passengers changing trains at the station.{{Cite web|date=4 August 2015|title=Plans to split Northern Line in two move forward another step|url=https://www.railtechnologymagazine.com/Rail-News/plans-to-split-northern-line-in-two-move-forward-another-step|url-status=live|access-date=13 September 2021|website=Rail Technology Magazine|archive-date=13 September 2021|archive-url=https://web.archive.org/web/20210913212544/https://www.railtechnologymagazine.com/Rail-News/plans-to-split-northern-line-in-two-move-forward-another-step}}{{cite web|date=2017|title=Improving capacity at Camden Town station|url=https://consultations.tfl.gov.uk/tube/camden-town-station-upgrade/|access-date=20 February 2018|website=Transport for London|archive-date=21 February 2018|archive-url=https://web.archive.org/web/20180221100254/https://consultations.tfl.gov.uk/tube/camden-town-station-upgrade/|url-status=live}} Detailed report, with updated timeline etc. In 2018, plans to upgrade and rebuild Camden Town station were placed indefinitely on hold, due to TfL's financial situation.{{Cite news|last=Topham|first=Gwyn|date=11 December 2018|title=Major tube upgrades shelved as TfL struggles to balance books|language=en-GB|work=The Guardian|url=https://www.theguardian.com/uk-news/2018/dec/11/major-tube-upgrades-shelved-as-tfl-struggles-to-balance-books|access-date=26 January 2020|issn=0261-3077|archive-date=26 December 2019|archive-url=https://web.archive.org/web/20191226092007/https://www.theguardian.com/uk-news/2018/dec/11/major-tube-upgrades-shelved-as-tfl-struggles-to-balance-books|url-status=live}}

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Category:Transport in the London Borough of Wandsworth

Category:Battersea

Category:Nine Elms

Category:Extensions to the London Underground

Category:Railway lines opened in 2021

Category:2021 establishments in England

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