The British domestic and foreign counterintelligence service responsible for national internal security.
Military Intelligence, section five; a former official and present-day popular name for the counterintelligence agency of the British Government. MI5 was formed in 1909 as the Secret Service Bureau.
by Dancing with Fire September 5, 2012
Get the MI5 mug.
5th section of military intelligence.


British data gathering security service. Mainly concerned with internal affairs, as opposed to more field active MI6 (Think James Bond) which follows foreign affairs.
MI5 concern themselves with internal affairs and counter-espionage
by Gumba Gumba April 13, 2004
Get the MI5 mug.
British intelligence agency.
They secretly have death squads that operate in Britain which disappear (murder) homeless people and other members of the public they deem unfit to live!
by Weal donald twump August 1, 2017
Get the mi5. mug.