There are very few pre-fabricated huts in 100 Places that Made Britain’s selection of significant historic places. But the wooden buildings that were erected in 1939 on the lawn of the mansion of Bletchley Park, now on the outskirts of Milton Keynes, deserve their place. They were at the heart of the operation to break the codes of the German and Japanese forces during the Second World War.
What happened at Bletchley was kept secret for decades after the war, and it wasn’t until the 1970s that information began to come out. The 1991 film Enigma brought the story to wider attention, but it’s only in the last few years that the place has opened as a heritage attraction and museum.
What visitors see now is the curious 19th-century Gothic mansion surrounded by a mass of wooden huts and later brick extensions from the war years. If you want an authentic wartime experience, here is as good a place as any to come. It feels in parts as if the site were still stuck in the 1940s. As Patricia Fara observes: ‘In most museums you see all the objects laid out in cases, often modern cases, so there’s very little connection between what you see inside the case and the building itself. But when you go to Bletchley, the buildings themselves are part of the museum. You’re wandering around these old huts exactly where everything was happening.’
So what was happening? Bletchley Park was taken over by the Government Code and Cypher School in 1938. Initially, the staff worked in the mansion and its adjoining buildings, but as the scale of the operation increased, the wooden huts and brick buildings were erected.
Thousands of people were employed here by the end of the war, and they were engaged in the business of decoding, translating and analysing the correspondence of the German armed forces. The information they gathered was dispatched from here to intelligence officers in London.
The most famous person to have worked at Bletchley was Alan Turing, a key figure in the development of the modern computer. You can pop your head around the door of the office where he worked within one of the pre-fab huts. He devised a machine called a Bombe that was used to break the codes of the famous German Enigma encryption machine.
The Bombe, a large and complicated-looking contraption of rotors, colour-coded drums and great snakes of wire, was developed from a device created by Polish code-breakers before the war (there is a memorial to the important Polish contribution in the stable yard at Bletchley). A rebuilt Turing Bombe is on display in the museum in Block B. To look at it is to be in awe not only of Turing’s inventiveness, but also of the skill of the Wrens who had to operate these room-sized machines (there were some 200 or so in use during the war). It looks to have been a devilish job of rewiring and resetting every time a new batch of codes was to be worked on.
In the museum you can also see various Enigma machines (which look like typewriters with rotors) of the sort that the Bombe was designed to counter. One of these was famously stolen from the museum in 2000 and then bizarrely posted to the BBC journalist Jeremy Paxman. It is now displayed in what one presumes is a very strong glass case.
The intelligence provided by the Bletchley Park code-breakers is now recognised by historians as a vital contribution to the Allies’ successful conclusion of the war. It has been suggested that the quality and quantity of information the code-breakers were able to pass on might have shortened the war by two years. According to Fara, ‘Although a lot of it is still classified, there’s more and more information coming out that shows we knew in advance what a lot of the German plans were, and so were able to take pre-emptive action. It’s pretty clear that Bletchley did have a decisive role to play in the war.’
Having provided critical intelligence that, among other things, helped protect shipping in the Battle of the Atlantic in the early 1940s, the success of the code-breaking operation was challenged in 1942. The Germans brought in a new version of the Enigma machine, which Turing and others had to deal with through improvements to the Bombe, and meanwhile a different cipher (the Lorenz) was adopted for messages between Hitler and his high command.
Another hero of Bletchley Park, Tommy Flowers, built Colossus, the first programmable electronic computer to counter Lorenz. This machine helped break the new German codes, and also paved the way for the computer revolution.
A Colossus machine has been rebuilt at Bletchley Park. Housed in one of the huts, like the Turing Bombe it takes up most of a room, and it’s all valves, whirring tapes, switches and wires. If you’re lucky, there will be one of the rebuild project volunteers there, delving into the innards of the device. Indeed, part of the atmosphere of the place today derives from the volunteers and enthusiasts who’ve been rebuilding the wartime machines. It’s taken a lot of skilled work over many years from these people to recreate them.
Their involvement gives Bletchley Park a friendly, low-key atmosphere that feels somehow particularly appropriate to the story; it lends it the sort of understated Britishness that one tends to associate with the war years. That sensation is accentuated by the bike sheds, some with archaic bicycles on racks, that proliferate around the site: the staff were not billeted at Bletchley Park, so these clandestine code-breakers were cycling in from their lodgings every day to get to work on their classified mission.
If it sounds more bike-clip and spectacles than cloak and dagger, the secrecy that nevertheless surrounded what went on here was jealously protected after the end of the Second World War. It was deemed crucial that the Soviet Union, Britain’s one-time wartime ally but latterly cold war adversary, did not learn the extent of the code-breaking work. As everything was kept hush-hush for decades, Bletchley perhaps still doesn’t get quite the recognition it should for its place in the Second World War, and indeed in computing history. All the more reason to pay a visit now.
Nominated by Patricia Fara, senior tutor, Clare College, University of Cambridge
This is an extract from the BBC History Magazine book 100 Places that made Britain, by David Musgrove, published on 2 June 2011