If you’re unsure of who does what among the UK intelligence agencies, here’s THE INTELLIGENCE TRAIL quick introduction to them. You can also download the National Intelligence Machinery booklet from the Cabinet Office.



Established in 1909 as the domestic section of the Secret Service Bureau. Previously known as MO5, and MO5(g), it became known as MI5 in 1916. Although the organisation’s official title is that of the Security Service, the MI5 name continues to be widely used. The Service is primarily responsible for counter- terrorism and counter-espionage. Previously it was also responsible for counter-subversion. The Service is headquartered in Thames House on London’s Millbank. Also based within Thames House is the multi-agency Joint Terrorism Analysis Centre (JTAC)

The first Director of the Service was Sir Vernon Kell, who held the position from 1909-1940: his 31 year tenure has never been beaten by anyone in any other British governmental agency. Since 1941, the head of the Service has been known as the Director General (DG). The current DG is Jonathan Evans, who reports to the Home Secretary.  Visit the official Security Service website




Officially known as the Secret Intelligence Service (SIS), and like MI5, established in 1909 as the foreign section of the Secret Service Bureau. It is the oldest continuously operating foreign intelligence service in the world. Throughout its lifetime, the Service has been known by other names and designations including MI1( c ). The MI6 name evolved in the 1930’s and despite not being officially referred to as such for several decades, it remains a commonly used name employed by many around the world.  

SIS are headquartered at 85 Vauxhall Cross on the south bank of the River Thames , adjacent to Vauxhall Bridge. The striking gold- and green-coloured building was designed by architect Terry Farrell. The current Chief is Sir John Sawyers, and reports to the Foreign Secretary. 

Visit the offical Secret Intelligence Service website




Whilst the ‘Trail concentrates on MI5 and MI6, other organisations may pop up in conversation. These include:-



Originally known as the Government Code and Cypher School until 1939 (officially in 1946) GCHQ is also answerable to the Foreign Secretary. It is tasked with SIGINT (Signals Intelligence) and information assurance responsibilities, working closely with the US National Security Agency.

The organisation is perhaps most well known for its WWII codebreaking work at Bletchley Park. In the 1950’s the organisation moved to Cheltenham (approx. 95 miles from London). The current Director is Ian Lobban.  Visit the official GCHQ website

Defence Intelligence Staff (DIS)

Part of the Ministry of Defence and headed by the Chief of Defence Intelligence (CDI), the DIS collects and analyses intelligence from all sources (overt and covert) relating to ongoing military operations, contingency planning, early warning of threats or situations, and analysing emerging threats. Their output is used not only the British government but also NATO and the EU.

As well as being based in the Old War Office on Whitehall, the DIS occupies other London facilities. The Defence College of Intelligence is based at RAF Chicksands, also home to the Intelligence Corps Museum  You can visit the official DIS webpage



Joint Intelligence Committee (JIC)

Residing within the Cabinet Office, the JIC assesses and reviews intelligence from the separate UK intelligence agencies and advises Government accordingly.

For more information regarding its role visit the JIC page on the Cabinet Office website.



National Security Council (NSC)

Also residing within the Cabinet Office, the NSC provides an opportunity for discussion on wider national security issues, of which intelligence matters are included.  Visit the NSC page on the Cabinet Office website



Intelligence and Security Committee (ISC)

The administration, expenditure and policies of the UK intelligence agencies are scrutinised by the ISC, comprising cross-party Members of Parliament. Instead of reporting to Parliament like other Parliamentary Select Committees, they report to the Prime Minister (although the reports, together with the Prime Minister’s response are subsequently debated in Parliament). The ISC Annual Reports can be downloaded, although you’ll quickly get used to the *** throughout the reports, where classified information has been redacted!  Visit the ISC website