Second world war code-breaking centre in Buckinghamshire was the forerunner of GCHQ
It was called the Intelligence Factory: a warren of rooms and offices in which, by the end of the war, thousands of people worked round the clock decoding and processing enemy communications.
Block A at Bletchley Park, the top secret second world war code-breaking centre in Buckinghamshire that was the forerunner of GCHQ, has been restored and opens to the public for the first time on Thursday. Using testimonies from veterans, surviving documents and photographs, and interactive reconstructions, the exhibition shows the industrial scale of the operation that was critical to the allied victory.