Description
The Security Service, also 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 (UK).
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.
Organisation
The Security Service comes under the authority of the Home Secretary within the Cabinet. The service is headed by a Director General (DG) at the grade of a Permanent Secretary of the Civil Service, who is directly supported by an internal security organisation, secretariat, legal advisory branch, and information services branch. The Deputy Director General is responsible for the operational activity of the service, being responsible for four branches; international counter-terrorism, National Security Advice Centre (counter proliferation and counter espionage), Irish and domestic counter-terrorism, and technical and surveillance operations.
The service is directed by the Joint Intelligence Committee for intelligence operational priorities. It liaises with SIS, GCHQ, DI, and a number of other bodies within the British government, and industrial base. It is overseen by the Intelligence and Security Committee of Members of Parliament, who are directly appointed by the Prime Minister, and by the Investigatory Powers Commissioner. Judicial oversight of the service's conduct is exercised by the Investigatory Powers Tribunal.
Operations of the service are required to be proportionate, and compliant with British legislation, including the Regulation of Investigatory Powers Act 2000, the Investigatory Powers Act 2016, the Data Protection Act 2018, and various other items of legislation. Information held by the service is exempt from disclosure under section 23 of the Freedom of Information Act 2000.
All employees of the service are bound by the Official Secrets Act. In certain circumstances, officers handling agents or informers may authorise them to carry out activity which would otherwise be criminal within the UK.
The current Director General is Ken McCallum, who succeeded Andrew Parker in April 2020.
The service marked its centenary in 2009 by publishing an official history titled The Defence of the Realm: The Authorised History of MI5, written by Christopher Andrew, Professor of Modern and Contemporary History at Cambridge University.
Members of the Security Service are recognised annually by King Charles III (formerly the Prince of Wales) at the Prince of Wales's Intelligence Community Awards at St James's Palace or Clarence House alongside members of the Secret Intelligence Service (MI6), and GCHQ. Awards and citations are given to teams within the agencies as well as individuals.
