United Kingdom

Founded in 1909 as the foreign section of the Secret Service Bureau, SIS collects intelligence abroad and is known to the public a...

MI5 was founded in 1909 to counter German espionage and has worked against subversion, sabotage, and terrorism ever since. It oper...

GCHQ began in 1919 as the Government Code and Cypher School, the cryptanalytic successor to wartime Room 40. Its wartime home at B...

SOE was formed in 1940 on the instruction of Winston Churchill to set Europe ablaze. It armed resistance movements, blew up infras...

Operation Mincemeat planted fabricated invasion documents on the body of a dead man dressed as a Royal Marines officer, allowing i...

Operation Fortitude built a phantom army to convince Germany the 1944 landing would come at the Pas de Calais. Fake radio traffic,...

Ultra was the intelligence derived from breaking German Enigma and later Lorenz ciphers at Bletchley Park, building on prewar Poli...

The Cambridge Five, Kim Philby, Donald Maclean, Guy Burgess, Anthony Blunt, and John Cairncross, were recruited at Cambridge in th...

Kim Philby worked for Soviet intelligence from the 1930s while rising inside the Secret Intelligence Service to head its anti-Sovi...

George Blake was recruited by the KGB while a prisoner in North Korea and betrayed Western operations for years, most famously rev...

The Double-Cross System, run by the wartime Twenty Committee, caught every German agent sent to Britain and turned them into chann...

Vasili Mitrokhin, a KGB archivist, spent years secretly copying foreign intelligence files before defecting to Britain in 1992, wh...

The Zimmermann Telegram, decrypted in Room 40 of British naval intelligence in January 1917, revealed Germany offering Mexico an a...

Formed in 1919 from the naval codebreakers of Room 40 and their army counterparts, the Government Code and Cypher School worked on...

Room 40 was set up in the Admiralty Old Building in 1914 under Sir Alfred Ewing, with Captain William Reginald Hall, Director of N...

Klaus Fuchs, a German born physicist and communist who fled the Nazis to Britain, worked on the British atomic project and then at...

A Spaniard who volunteered to spy for Britain, Juan Pujol Garcia first talked the Germans into recruiting him and then fed them in...