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MI5

British domestic security agency

Also known as Security Service · United Kingdom Security Service · Military Intelligence, Section 5 · Box 500

Instance of: security agency
Country: United Kingdom
Located in: City of Westminster
Founded: 1909
Website: mi5.gov.uk

Overview

From Wikipedia, the free encyclopedia · Read full article · Text CC BY-SA 4.0

The Security Service, commonly known as MI5, 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. Within the civil service community, the service is colloquially known as Box, or Box 500, after its official wartime address of PO Box 500; its current address is PO Box 3255, London SW1P 1AE.

Overview

All data

47 statements · 15% with external sources · numbers in brackets are citations

Applies to jurisdiction: United Kingdom
Headquarters: Thames House(since 1994) coordinates: 51.4939°N, 0.1256°W
140 Gower Street(1976–1994)
Leconfield House(1945–1976)
Chair: Andrew Parker
Field of work: counterintelligence
Motto text: Regnum Defende
Position held by head of the organization: Director General of MI5
Participated in conflict: World War II
Category for employees of the organization: Category:MI5 personnel
Parent: Home Office
Cabinet of the United Kingdom
Name: ꠄꠝ ꠀꠁ ꠚꠣꠁꠜ
Hashtag: mi5
Native label: Security Service MI5

On other databases

27 identifiers linking MI5 across the web's reference databases

Data quality

statements

15%

externally sourced

Source last edited July 5, 2026. AIDB refreshes this page daily.

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AIDB. (2026). MI5 (Q210175). Retrieved from https://aidb.si/e/mi5-Q210175