Official Secrets Act 1939

{{Short description|Act of Parliament of the United Kingdom}}

{{Use dmy dates|date=April 2025}}

{{Use British English|date=April 2025}}

{{Infobox UK legislation

| short_title = Official Secrets Act 1939{{efn|name=st|reference=Section 2(1).}}

| type = Act

| parliament = Parliament of the United Kingdom

| long_title = An Act to amend section six of the Official Secrets Act 1920.

| year =

| citation = 2 & 3 Geo. 6. c. 121

| territorial_extent = United Kingdom{{efn|Section 2(2).}}

| royal_assent = 23 November 1939

| commencement = 23 November 1939{{efn|The Acts of Parliament (Commencement) Act 1793.}}

| expiry_date =

| repeal_date = 20 December 2023

| amends = Official Secrets Act 1920

| replaces =

| amendments =

| repealing_legislation = National Security Act 2023

| related_legislation = Official Secrets Act 1911

| status = Repealed

| original_text = http://www.legislation.gov.uk/ukpga/1939/121/enacted

| revised_text = http://www.legislation.gov.uk/ukpga/1939/121

| use_new_UK-LEG = yes

}}

The Official Secrets Act 1939{{efn|name=st}} (2 & 3 Geo. 6. c. 121) was an act of the Parliament of the United Kingdom. It substituted a new section 6 into the Official Secrets Act 1920, which limited the scope of that offence to offences under section 1 of the Official Secrets Act 1911 (it had formerly applied to all offences under the Official Secrets Act 1911 and to all offences under that act).

It was enacted in reaction to the "Sandys affair" in 1938, when Duncan Sandys MP was threatened with prosecution under section 6 in an attempt to get him to disclose who had given him information about the inadequate state of the air defences around London.

The whole act was repealed by and replaced with the National Security Act 2023.{{cite news |title=National Security Act Factsheet - Home Office in the media |url=https://homeofficemedia.blog.gov.uk/2023/07/11/national-security-act-factsheet/ |access-date=24 October 2023 |work=homeofficemedia.blog.gov.uk}}{{Cite legislation UK |type=act |year=2023 |chapter=32 |act=National Security Act 2023|section= |schedule=18 |date=11 July 2023 |accessdate=20 December 2023}}

{{Cite legislation UK |type=si |year=2023 |number=1272 |si=The National Security Act 2023 (Commencement No. 1 and Saving Provision) Regulations 2023 |regulation= |date=27 November 2023 |accessdate=20 December 2023}}