Andrew Hodges, the biographer of Alan Turing, took this picture of Bletchley Park huts as they appeared in 1998. He describes the photo: "Hut Eight, where Alan Turing worked on the naval Enigma, is in the centre of the picture. To the left is Hut Six (Army and Air Force signals). To the right is Hut One." For more of Hodge's background information on Station X and Turing, visit his "Alan Turing: The Enigma" website.
Code breakers assigned to Hut 8 were charged with cracking Germany’s naval Engima code. It was the most-difficult job of all at Bletchely Park (also known as Station X).
The first “huts” were built at Bletchley Park during 1939. Before that, however, a handful of people in pre-war Britain - using the valuable information and Enigma replicas which the Poles had provided - were already trying to understand and break Germany’s coding system.
Much of that early work was done at the Government Codes & Ciphers School (GC&CS) located, during 1938, in London. Alfred Dillwyn ("Dilly") Knox was an early code breaker; so was Peter Twinn. In September of 1939, they were joined by Gordon Welchman, who was later in charge of Hut 6.
Historical records tell us that Hut 8 (which is shaded in this site view) was likely built in early 1940. Its first occupant was the GC&CS group working on Germany’s naval Enigma code.
Who were the people working in Hut 8?
All of these individuals were highly intelligent people who were among Britain’s brightest math minds at the time.
And then there was Alan Turing. His 1936 paper, “On Computable Numbers” - which he wrote, as a student, while working on his PhD at Princeton - became a cornerstone of today’s “digital age.”
What did Turing mean by "computable numbers?"
The "computable" numbers may be described briefly as the real numbers whose expressions as a decimal are calculable by finite means... a number is computable if its decimal can be written down by a machine. (See the first paragraph of Turing's paper, online via Oxford University.)
It was that paper, among other things, which caused British government officials to recruit Turing (from Cambridge) to work at Bleachley Park.
And ... it was in working-up that paper where Turing's mathematical musings led him to envision a machine in which symbols, representing instructions, were no different from symbols representing numbers.
In other words ... Turing imagined today's computers before today's technology even existed.
Turing’s biographer, Andrew Hodges, describes the impact of Turing’s “Computable Numbers” paper with these words:
It is now almost impossible to read Turing's 1936 work without thinking of a Turing machine as a computer program, and the Universal Turing Machine as the computer on which different programs can be run...
We are now so familiar with the idea of the computer as a fixed piece of hardware, requiring only fresh software to make it do entirely different things, that it is hard to imagine the world without it.
But Turing imagined the Universal Turing Machine ten years before it could be implemented in electronics.
Now you can use your computer to simulate the working of a Turing machine, and so see on the screen what in 1936 was only possible in Turing's imagination. This is no accident! — the whole point is that the computer embodies the principle of a Universal Turing machine, which can simulate any Turing machine.
It was also essential to Turing's 1936 work that a Turing machine could be thought of as data to be read and manipulated by another Turing machine — this is the principle of the modifiable stored program on which all computing now depends.
With Turing, Stewart Menzies had the perfect person to head the Hut 8 code-breaking team.