Government Communications Headquarters

British intelligence agency

The Government Communications Headquarters (GCHQ) is a British intelligence agency. Its work continues that of the Bletchley Park team.

Government Communications Headquarters
"The Doughnut", the headquarters of the GCHQ
Agency overview
Formed1919 as the GC&CS
Preceding agencies
  • MI1b (Army)
  • NID25 (Royal Navy)
JurisdictionBritish Government
HeadquartersThe Doughnut, Cheltenham, UK
51°53′58″N 2°07′28″W / 51.89944°N 2.12444°W / 51.89944; -2.12444
Employees6,132 (fy 2012–13)[1]
Annual budgetSingle Intelligence Account
Minister responsible
Agency executive

GCHQ collects, analyses and passes on signals from many parts of the world. This is called "signals intelligence" (SIGINT). It would include all forms of free-to-air signals plus many interceptions of covert communication. Computers scan the signals for key words of phrases, and flag any which contain key words.

The second job of GCHQ is to crack the cyphers (codes) of sources it is interested in. It is this part of the work which Bletchley Park used to do. It also arranges for our own secret transmissions to be coded securely. This is the world of cryptography, ways and means of getting into other people's secrets, and keeping our secrets secure. This is done by CESG (Communications-Electronics Security Group).

As an organisation, GCHQ is under the guidance of the Joint Intelligence Committee (JIC). GCHQ was started after the First World War as the Government Code and Cypher School (GCCS or GC&CS), by which name it was known until 1946.[2] As part of ECHELON, it works with Intelligence agencies from other allied countries.


  1. Intelligence and Security Committee of Parliament Annual Report 2012–2013 (PDF). 2013. p. 40. ISBN 978-0-10-298652-5. Retrieved 29 December 2013.
  2. Alvarez, David 2001. Most helpful and cooperative: GC&CS and the development of American diplomatic cryptanalysis, 1941-1942. In Smith, Michael & Erskine, Ralph (eds) Action this day: Bletchley Park from the breaking of the Enigma code to the birth of the modern computer. Bantam Press. ISBN 978-0593049105