A 'Bombe' code-breaking machine at Bletchley Park, 1943.
© Bletchley Park Trust / Science & Society Picture Library
This shows the rear plugging of the Bombe decoding machine in hut 11a at Bletchley Park, Buckinghamshire, the British forces' intelligence centre during WWII. The cryptographers at Bletchley Park deciphered top- secret military communiques between Hitler and his armed forces. These communiques were encrypted in the 'enigma' code which the Germans considered unbreakable, but the codebreakers at Bletchley cracked the code with the help of Bombe machines, and so the Allies victory.