MI5: Quick Facts

Written and fact-checked by

The Information Architects of Encyclopaedia Britannica

Last updated

Nov. 13, 2026

News •

U.S. Army officer arrested in U.K. on suspicion of trying to steal secrets for Russia • Nov. 10, 2026, 4:17 PM ET (The Spokane Spokesman-Review)

MI5 agent handler's pistol sells for four times estimate • Nov. 5, 2026, 10:50 AM ET (BBC)

Z.ai founders worked on research funded by China institute that Britain tied to spies • Oct. 19, 2026, 11:35 PM ET (Straits Times)

MI5 chief says Iran is targeting military sites and suspected plot at RAF Fairford is 'not unique’ • Oct. 13, 2026, 9:32 PM ET (AP)

Facts

Also Known As	Security Service • British Security Service • BSS
Date	1909 - present
Areas Of Involvement	intelligence • counterespionage
Related People	Anthony Blunt

Topics

Central Intelligence Agency National Aeronautics and Space Administration KGB Federal Bureau of Investigation National Security Agency MI6 Mossad U.S. Secret Service U.S. Department of Defense Environmental Protection Agency