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WW1 Signals Exchange, Somme, France, 1916

Key Figures in UK Sigint

Tens of thousands of people have worked in Sigint over the years – many of them people with unique skills and extraordinary ingenuity who have made a huge difference to the defence of this nation and its interests. A very few of them are described here.
WW1 Signals Exchange, Somme, France, 1916


Britain’s Signals Intelligence effort essentially dates from the beginning of World War I. A number of radio intercept stations were then created, and an increasing number of cryptanalysts, linguists and radio traffic analysts enjoyed considerable success in decrypting messages sent by Germany and its allies and in disseminating this intelligence to where it was needed.
Bletchley Park main house

​WWII: Bletchley Park

Bletchley Park, a country house in Buckinghamshire, was bought by SIS in 1938 as a site to which the Government Code & Cypher School and SIS could be evacuated when war came.
It was widely expected that London would be the target of a massive aerial assault at the very start of any war.
C Block, Oakley. Clean-lined early 1960s 3-storey office block

Post War

After the war, the Government Code & Cipher School changed its name officially to GCHQ and moved its headquarters to Eastcote in Middlesex (1946), and later to Cheltenham in Gloucestershire (1950s).
The Central Training School stayed at Bletchley Park until 1987, when it moved to Culmhead (near Taunton in Somerset).

Recent history: technology challenges

Since World War II, the communications environment has changed beyond all recognition, presenting GCHQ with a series of formidable technical challenges as it attempts to follow its targets.
Read more >>​

Recent history: the changing global environment

Following the collapse of the Warsaw Pact in 1991, GCHQ broadened its focus away from the Soviet Bloc to encompass a wider range of global targets. The more unpredictable nature of the threat required much greater agility from GCHQ, and the development of new areas of expertise.
The Bletchley Park Commorative badge

​Bletchley Park Commemorative Badge

On behalf of Her Majesty's Government, GCHQ is delighted to recognise the vital service of those who worked at Bletchley Park and its outstations during World War II, by presenting surviving veterans with a commemorative badge.
Old black and white photo of people at Bletchley Park

​Bletchley Park Veterans

If you know of someone who was a Bletchley Park veteran and is sadly no longer with us, please register them.

Historical records and releases

The Public Records Act 1958 requires government departments to transfer records to the National Archives 30 years after creation.
GCHQ has a blanket exemption from this requirement, but has made voluntary releases which appear on the National Archives catalogue under the HW series.