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.
Block A opened in late 1942, built to house the ever-expanding number of people needed to decode, analyse and process a growing mountain of war communications. Bletchley Park bosses scrambled to recruit more and more people – 75% of them women, many in their late teens or early 20s, mostly doing tedious, repetitive tasks in conditions of extreme secrecy.
By the end of 1945, almost 9,000 people were working three shifts a day at Bletchley. They were billeted with local residents, or housed in specially constructed huts containing rows of camp beds, and fed canteen meals of mince and potatoes or corned beef with prunes.
On arrival, all had to sign a document headed “Secrecy”, which instructed them to never talk about their work at meals, on transport or even “by your own fireside”. It warned: “There is nothing to be gained by chatter but the satisfaction of idle vanity, or idle curiosity: there is everything to be lost.”
For most, it was a far cry from the experience of Alan Turing, the brilliant mathematician who cracked the Enigma code and whose story was told in the Oscar-nominated 2014 film The Imitation Game.
“Turing was a genius, who worked largely in intellectual isolation,” said Thomas Cheetham, research officer at Bletchley Park. “In fact, this place was like a factory – busy, bustling, noisy, lots of people doing small tasks. For many, it was their first job – the average age was 19 – and it was quite boring work. And they were never given the big picture of what was being achieved at Bletchley.”
The exhibition includes a recreation of the naval plotting room, where the movements of ships and submarines were tracked by pins and string placed in floor-to-ceiling maps.
An original Hollerith machine that organised and processed data using 2m individual punch cards every week – a job that today’s computer technology could complete in moments – stands in another room.
Pneumatic tubes, known as “spit and suck”, kept vital information flowing around Block A. Its distinctive whooshing sound, along with the clatter of the Hollerith and the general background noise of people working at close quarters, provided a constant soundtrack to the centre.
The 24/7 activity was backed up by a gargantuan management operation, with thousands of memos posted on noticeboards. One, dated 16 June 1942, states that “it is NOT permissible to issue second helpings” at mealtimes due to strict rationing. Another, issued on 24 February 1943, advised that “beer will be available daily in Hut 2 (Recreation Hut) between noon and 2pm, and 6pm and 8pm”.
Kay Pickett (née Harrison), now 96, who started work at Bletchley Park in June 1944 at the age of 18, said she had no real idea of the significance of the work until much later in her life. “Everything was so secret, and we weren’t allowed to talk about it. Now I know how important it was.”
Erica Munro, exhibitions manager, said: “In the intelligence factory, there was a very strong female experience – partly through the sheer numbers, and partly through the variety of work that they were doing. It’s been a pleasure to include so many female voices in audio points through the exhibition.”
The importance of Bletchley Park to the overall allied effort was “incalculable”, said Cheetham. “Everybody tried to do signals intelligence. Some countries were very bad at it. The Americans were quite good, but even they didn’t achieve what the British achieved at Bletchley Park: having one central signals intelligence centre that handled everything. Britain was so far ahead.”