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 | |
 Thames House, London | |
| Agency overview | |
|---|---|
| Formed | 7 October 1909 (as the Secret Service Bureau) |
| Jurisdiction | His Majesty's Government |
| Headquarters | Thames House, London, United Kingdom 51°29′38″N 0°07′32″W / 51.49389°N 0.12556°W |
| Motto | Regnum Defende (Defend the Realm) |
| Employees | 5,259[1] |
| Annual budget | Single Intelligence Account £3.711 billion (2021–22)[1] |
| Minister responsible | |
| Agency executive | |
| Website | www |
MI5 (Military Intelligence, Section 5),[2] officially the Security Service, is the United Kingdom's domestic counter-intelligence and security agency and is part of its intelligence machinery alongside the Secret Intelligence Service (MI6), Government Communications Headquarters (GCHQ), and Defence Intelligence (DI). MI5 is directed by the Joint Intelligence Committee (JIC), and the service is bound by the Security Service Act 1989. The service is directed to protect British parliamentary democracy and economic interests and to counter terrorism and espionage within the United Kingdom (UK). Within the civil service community, the service is colloquially known as Box,[3] or Box 500,[4] after its official wartime address of PO Box 500; its current address is PO Box 3255, London SW1P 1AE.[5]
The Security Service is derived from the Secret Service Bureau, founded in 1909. At the start of the First World War, it was responsible for the arrest of enemy spies, or suspected enemy spies. Throughout the First World War, Germany continually attempted to infiltrate Britain, but MI5 was able to identify most, if not all, of the agents dispatched. During the Second World War, it developed the Double-Cross System. This involved attempting to 'turn' captured agents wherever possible, and use them to mislead enemy intelligence agencies.
After the war, the service was instrumental in breaking up a large Soviet spy ring at the start of the 1970s. It then allegedly became involved in monitoring trade unions and left-wing politicians. It also assumed responsibility for the investigation of all Irish republican activity within Britain during The Troubles. Its role was then expanded to countering other forms of terrorism, particularly in more recent years the more widespread threat of Islamic extremism. In 1996, legislation formalised the extension of the Security Service's statutory remit to include supporting the law enforcement agencies in their work against serious crime.
- ^ a b Intelligence and Security Committee of Parliament "Annual Report 2021–2022"
- ^ "What's in a name?". www.MI5.gov.uk. MI5. Retrieved 14 May 2014.
- ^ "Annie Machon: my so called life as a spy". The Telegraph. 29 August 2010. Archived from the original on 11 January 2022. Retrieved 22 December 2020.
- ^ "MI5 edges out of the shadows: 42% of elite Security Service officers are women – Terrorists are main target – Bugging of Royal Family denied – Booklet outlines organisation". The Independent. 16 July 1993. Retrieved 22 December 2020.
- ^ Geraghty, Tony (2000). The Irish War. London: HarperCollins. ISBN 978-0-00638-674-2.