<body, history> A country house and grounds some 50 miles North of London, England, where highly secret work deciphering intercepted German military radio messages was carried out during World War Two. Thousands of people were working there at the end of the war, including a number of early computer pioneers such as Alan Turing. The nature and scale of the work has only emerged recently, with total secrecy having been observed by all the people involved. Throughout the war, Bletchley Park produced highly important strategic and tactical intelligence used by the Allies, (Churchill's "golden eggs"), and it has been claimed that the war in Europe was probably shortened by two years as a result. An exhibition of wartime code-breaking memorabilia, including an entire working Colossus, restored by Tony Sale, can be seen at Bletchley Park on alternate weekends. The Computer Conservation Society (CCS), a specialist group of the British Computer Society runs a museum on the site that includes a working Elliot mainframe computer and many early minicomputers and microcomputers. The CCS hope to have substantial facilities for storage and restoration of old artifacts, as well as archive, library and research facilities. Telephone: Bletchley Park Trust office +44 (908) 640 404 (office hours and open weekends). (1998-12-18)

Bletchley Park is an English country house and estate in Bletchley, Milton Keynes (Buckinghamshire) that became the principal centre of Allied code-breaking during the Second World War. The mansion was constructed during the years following 1883 for the financier and politician Sir Herbert Leon in the Victorian Gothic, Tudor, and Dutch Baroque styles, on the site of older buildings of the same name.

During World War II, the estate housed the Government Code and Cypher School (GC&CS), which regularly penetrated the secret communications of the Axis Powers – most importantly the German Enigma and Lorenz ciphers. The GC&CS team of codebreakers included Alan Turing, Gordon Welchman, Hugh Alexander, Bill Tutte, and Stuart Milner-Barry. The nature of the work at Bletchley remained secret until many years after the war.

According to the official historian of British Intelligence, the "Ultra" intelligence produced at Bletchley shortened the war by two to four years, and without it the outcome of the war would have been uncertain. The team at Bletchley Park devised automatic machinery to help with decryption, culminating in the development of Colossus, the world's first programmable digital electronic computer. Codebreaking operations at Bletchley Park came to an end in 1946 and all information about the wartime operations was classified until the mid-1970s.

After the war it had various uses including as a teacher-training college and local GPO headquarters. By 1990 the huts in which the codebreakers worked were being considered for demolition and redevelopment. The Bletchley Park Trust was formed in February 1992 to save large portions of the site from development.

More recently, Bletchley Park has been open to the public, featuring interpretive exhibits and huts that have been rebuilt to appear as they did during their wartime operations. It receives hundreds of thousands of visitors annually. The separate National Museum of Computing, which includes a working replica Bombe machine and a rebuilt Colossus computer, is housed in Block H on the site.

About 8,000 women worked in Bletchley Park, the central site for British cryptanalysts during World War II. Women constituted roughly 75% of the workforce there.