That historic mansion, and the remaining "huts" behind it housed the "Golf, Cheese and Chess Society" as it was mischievously nicknamed by many who worked there - GCCS - Government Code and Cypher School, the forerunner of the modern GCHQ. School it never was - some of the best brains in Britain worked there. The nearby railway station is about half way between Oxford and Cambridge, from which universities many of the best people were drawn, a good few in their early twenties.
Churchill called it "The goose which laid the golden eggs, but never cackled". A couple who met after the war, and married, followed the rules and never spoke about it to one another. After 1976, when its existence came to light when embargo dates were reached, they realised they'd worked there for several years, but had never met - not surprising, as at its peak, around 10,000 men and women filled the huts and the house - a shift system was in operation for most.
There's a
museum there now, with working enigma machines and "bombes" - chains of (basic, no keyboard) enigma machines running through possible wheel settings. This gives the lie to movies which show enigma machines being seized from German submarines and ships - GCCS didn't need 'em - they had hundreds. What they needed was the wheels (changed and added to as the war progressed) and the code books with initial wheel settings, changed daily.
I believe the museum also has a working
Colossus computer (or at least a good chunk of one), the world's first programmable computer, and necessarily top-secret for many years after the war. It was used (with several others later on) to decode the output of the "Super Enigma" machine - the Lorentz Cypher Machine. Colossus was never used on Enigma, despite what several movies, books, magazine articles and websites would have you believe.