GCHQ, the Government Communications Headquarters is based at a site near Cheltenham in Gloucestershire. It has two main functions, providing signals intelligence and information assurance (the protection of government communications, information systems and national infrastructure).
History of GCHQ
The Government Code and Cipher School (GC&CS) was formed in 1913 to break the diplomatic and military codes of foreign nations. Initially with a compliment of 25 cryptologists and 30 support staff. During the First World War they provided valuable signals intelligence (SIGINT).
In 1922 GC&CS was transfered to the control of the Foreign Office.
Towards the end of the 1930's as a second war in Europe became more likely GC&CS started recruiting talented mathematicians, chess players, professors and linguists to their new site at Bletchley Park. Among the recruits were the novelist and creator of James Bond, Ian Fleming and the mathematician, Alan Turing.
During the Second World War the staff at Station X as Bletchley Park was known broke the German Enigma codes providing the allies with crucial information, codenamed
"Ultra", regarding the disposition of German forces in all the theatres of operation. The cracking of the Naval Enigma codenamed "Shark" allowed the infamous U-boat "Wolfpacks" to be targetted. The exploits of the staff at Station X remained classified until the 1980's.
In 1946 GC&CS changed its name to Government Communications Headquarters (GCHQ) and moved to London briefly before moving to two sites in Cheltenham in 1952.
During the cold war GCHQ continued its codebreaking role, breaking military, diplomatic and economic communications of foreign nations especially the Soviet Union.
In 1994, after the end of the cold war, the Intelligence Services Act, altered GCHQ's remit to include the protection of national security, economic well-being and the detection and prevention of serious crime.
GCHQ's role can be best summed up by a quote by Robin Cook, a former Foreign Secretary.
'In a world in which information is increasingly the single most important commodity, GCHQ helps ensure that Britain can go forward with confidence'.