Bletchley Park - a secret for decades, now a visitor attraction
The wartime intelligence centre at Bletchley Park was restored and opened to the public in 2014. Here, I have attempted to give an idea of what went on and why...together with my personal photos of a recent visit...
(looking from the Mansion)
(inside the exhibition)
It’s 1938. With war in Europe increasingly likely, a first-rate intelligence and cipher-breaking operation was going to be necessary. The UK Government therefore acquired the Bletchley Park premises - mainly a mansion - in Buckinghamshire about fifty miles east of Cambridge. ‘Give them what they need!’ instructed Winston Churchill. So, it expanded over the ensuing years with the addition of many outbuildings and facilities for its workforce, which would eventually run well into the thousands. Its main operation was centred around code-cracking; deciphering messages sent by the ‘Enigma’ machines developed in Germany during the inter-war years. Other, more advanced machinery was to follow...
(an Enigma machine)
Robert Harris takes up the story:
‘The genius lay in the vast number of different permutations the Enigma could generate. Electric current on a standard Enigma flowed from keyboard to lamps (corresponding to letters) via a set of three wired rotors (at least one of which turned a notch every time a key was struck), and a plugboard with twenty-six jacks. The circuits changed constantly; their potential number was astronomical, but calculable.There were five different rotors to choose from (two were kept spare) which meant that they could be arranged in any one of sixty possible orders. Each rotor was slotted onto a spindle and had twenty-six possible starting positions. Twenty-six to the power of three was 17,576. Multiply that by the sixty potential rotor orders and you got 1,054,560. Multiply that by the possible number of plugboard connections - about 150 million million - and you were looking at a machine that had around 150 million million million starting positions. It didn't matter how many Enigma machines you captured, or how long you played with them. They were useless unless you knew the rotor order, the rotor starting positions, and the plugboard connections. And the Germans changed these daily, sometimes twice a day.
(The lake and the mansion)
The machine had only one tiny - but as it turns out, crucial - flaw. It could never encipher a letter as itself: an A could never emerge from it as an A, a B as a B, a C as a C…Nothing is ever itself. That was the great guiding principle in the breaking of Enigma, the infinitesimal weakness that the ‘bombes’ (electromechanical computers) exploited’. (Robert Harris, ‘Enigma’, 1995)
(a corridor in an outbuilding)
A lot of punched-card work went on at Bletchley, but it is to Alan Turing and Gordon Welchman that we owe the development of the first ‘Bombe’ machines used at Bletchley to help obtain the cipher keys. Such machines were hot, noisy and smelly but they speeded up the job. The whole process was quite complex - needless to say the resulting deciphered traffic had to be translated, and thereafter analysed for its usefulness. It would be a mistake to think that the machinery and its designers were the be-all and end-all of Bletchley. Skilled and dedicated staff were essential. Recruitment pulled in figures such as J R R Tolkien and also the future politician, Roy (later Lord) Jenkins. The operation was a success; it shortened the war, marked the beginnings of a new UK/US cooperation - but stayed secret for decades...
(a replica 'bombe' machine)
(Inside the Mansion) - the Commander's office)
(Round and about the Grounds and Mansion)
During the final eighteen months or so of the war, the ‘Colossus’ machines made an appearance. The brainchild of one Tommy Flowers, these machines differed from Turing’s in that they used thermionic valves - a technology that allowed them to operate at several MHz - not bad for a machine designed in the 1940’s even if it could fill a living room! The electronic computer had arrived.
The garage contained a few interesting vehicles - most notably this Packard (say Packr’d) 'Six' from 1940. A fleet of these was kitted out with specialist radio equipment, painted in camouflage and used by the service. The marque disappeared in 1958
A very thorough and interesting history of this form of code and cypher making and breaking generally, and the formation and work of Bletchley Park, is David Khan's Seizing The Enigma - The race to break the German U-boat codes, 1939-1943. (Frontline Books, London, and Naval Institute Press, Annapolis, Maryland, 1991, 1998, 2012.)
As well as the history, the book traces the invention in 1918, and development of, the 'Enigma' system, which was originally intended for commercial, not military, secrecy; and explains how it works. One point it brings out is that whilst the computers vastly increased the speed and efficiency of the cypher-analysing, indeed making it all possible, it still relied on teams of people carefully examining what the machines produced.
I have an unedited proof of the original book that the film was taken from... I know we captured the first machine from a u boat that the self destruct charges failed to detonate on... Lol my point was the Americans believe the movie more than fact 😂😂@Dlrannie
@Royrogers And they took everything to bits when they were finished! What we see now are reconstructions - of the 'bombe' machine. I've got a feeling they've rebuilt a 'colossus' somewhere, but didn't see it on my rounds. I think it's at a site next door.
@supersnipe possibly but the technology was so out of date when they moved the operations to chelthenham. Luckily at that time we had good relationships with the us
@supersnipe it was all broken up on Churchill's order, presumably for what were thought good security reasons - but oh what a short-sighted decision that turned out to be, by losing what had Britain's lead in developing electronic computers!
It is indeed a most interesting place to visit and undoubtedly played a major part in winning the war. It should be remembered that the Enigma was initially cracked by the Polish Cypher Bureau.
@Dlrannie Yep, the Poles were valuable collaborators in all this, they were on the case in the Thirties. The 'Bombe' idea, IIRC, was also one of theirs, as was the name. It was perfected by Turing, of course
In 1961 my grandpa went to Bletchley Park for training with GCHQ (Government Communications HQ) for 6 months. The mansion was used by the Post Office for training. There were one or two other departments like DWS (Diplomatic Wireless Service) and MCA (Ministry of Civil Aviation) that had small training establishments there. There was also an all-female teacher's training college on the site.
@ArishMell Yes, very true about the teams of people who worked there. Some famous names in there, too. My guidebook purchased on the day of my visit gives the number of people working there rising from 185 on 4th September, 1939 to 8,995 by 14th January, 1945!
I think there should be a collective memorial to all the clever ones and all those whose efforts and labours made it possible not just one of two have achieved fame
SW-User
hopefully theres a memorial in memory of Alan Turing there
