The Enigma of Bletchley Park: Britain's Best Kept Secret

Bletchley Park was the wartime home of the Government Code and Cypher School, where some of the greatest minds in Britain worked to break the codes used by the Axis powers. At its peak, over 10,000 people worked there — the majority of them women.

The most famous achievement was the breaking of the German Enigma cipher, but Bletchley also cracked the Lorenz cipher used for high-level German communications, and Japanese codes. The intelligence produced — codenamed Ultra — gave Allied commanders advance knowledge of enemy plans.

The secrecy was absolute. Workers in one hut knew nothing of what went on in the next. Veterans were bound by the Official Secrets Act and most took their secret to the grave. It was not until the 1970s that the story began to emerge, and many families only learned of their relatives' wartime roles decades after their deaths.