National hf communications receiver, type HRO M, Bletchley Park, 1997.
© Science Museum / Science & Society Picture Library
National hf communications receiver, type HRO M shown in a re-creation of a radio intercept room at Bletchley Park, Buckinghamshire. Bletchley Park was the British forces' intelligence centre during World War II, where cryptographers 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 aided the Allies victory.