Government Communications Headquarters

The Government Communications Headquarters (GCHQ), has the twin roles of providing signals intelligence for government - the interception and analysis of communications in support of national security (with particular reference to defence and foreign policy), in the interests of the UK's economic well-being, and for the prevention and detection of serious crime

What is now GCHQ began life as The Government Code and Cypher School (GCCS) in 1919, an organisation combining the First World War naval code breakers of Naval Intelligence Department 25 (popularly known as ‘Room 40’), and the army code breakers of Military Intelligence Branch 1B.

During the Second World War GCCS staff (working principally at Bletchley Park) broke numerous codes and ciphers, including most famously the German Enigma machine. In 1946 the name of GCCS was changed to Government Communication Headquarters. The organisation was put on a statutory footing by the Intelligence Services Act 1994

Why not send an encoded message to a friend using our online interactive codemaster

Browse the files relating to GCHQ records in our catalogue

Go to the Government Communications Headquarters (GCHQ) website to read more