Rapid transit in the United Kingdom

! width=90|City

! width=150|System

! width=120|Start of operations

! System length

! Lines{{efn|name=lines|Indicates lines that are in operation for operational systems, lines that are under construction for under construction systems and proposed lines for proposed systems.}}

! Stations{{efn|name=stations|Indicates stations that are in operation for operational systems, stations that are under construction for under construction systems and proposed stations for proposed systems.}}

! width=120|Voltage

! class=unsortable|Notes

| London Underground

| 10 January 1863

| 402 km

| 11

| 272

|630 V DC fourth rail

| The oldest rapid transit system, incorporating the world's first underground railway.

| Docklands Light Railway

| 31 August 1987

| 34 km

| 7 (routes)

| 45

|750 V DC third rail

| An automated light metro system opened in 1987 to serve the redeveloped Docklands area of London.

| Tyne and Wear Metro

| 11 August 1980

| 74.5 km

| 2

| 60

|1500 V DC OLE

|A rapid transit and light rail system in North East England, serving Newcastle upon Tyne, Gateshead, South Tyneside, North Tyneside and Sunderland in the Tyne and Wear region.

| Glasgow Subway

| 14 December 1896

| 10.5 km

| 1

| 15

| 600 V DC third rail

|An underground light metro line in Glasgow. It is the third-oldest underground metro system in the world after the London Underground and the Budapest Metro, and the only underground metro system in the British Isles outside England.

! City

! System

! Start of operations

! System length

! Lines{{efn|name=lines}}

! Stations{{efn|name=stations}}

! Voltage

! class=unsortable|Notes

| London Overground

| 11 November 2007

| 123.6 km (official lines)

| 8

| 112

|third-rail 750 V DC and 25 kV 50 Hz AC OLE

|A suburban rail network in the United Kingdom, serving a large part of Greater London and parts of Hertfordshire. Contains the East London line, a former London Underground line.

| Elizabeth line

| 24 May 2022

| 136 km

| 1

| 41

|25 kV 50 Hz AC OLE

| A railway line in London and its environs constructed under the Crossrail project, providing a new east-west route across Greater London. It provides a high-frequency commuter/suburban passenger service linking parts of Berkshire and Buckinghamshire, via central London, to Essex and South East London, relieving the pressure on other railway services.

| Merseyrail

| 1886 (Mersey Railway)

| 121 km (official lines)

| 2 official and
one unofficial line)

| 68

|third-rail 750 V DC

|A commuter rail network, in the Liverpool City Region, England. The network has 68 stations running on 75 miles of route, of which 6.5 miles are underground, forming one of the most heavily used railway networks in the UK outside London.

|South Wales Metro

|2025

|169.2 km

|9

|94

|25 kV AC OLE

|