Bletchley, England: The code-breaking mansion

June 30, 2015

The rundown house in the country discovered by "Captain Ridley's Shooting Party"

AS YOU ride into Milton Keynes, a sign proclaims it "Home of the Code-breakers". What this means isn't evident if your first language isn't English. In French, le code can mean the law of the land. So a French friend seeing it for the first time asked her husband why a town would celebrate its criminals.

The sad aspect to the sign is that it looks back seven decades and suggests Milton Keynes, old or new, has had nothing to brag about since. Which the local council would dispute but which I rather think is true.

Anyway, the government was looking during the war for somewhere out of the way to house the country's mathematicians, crossword demons and other eccentrics who could break codes. London was ruled out and so were the universities. Too obvious. So Whitehall found a mansion in the countryside, spiritually more remote than now, on which the lease was available. And in late August 1938 "Captain Ridley’s Shooting Party" turned up with a Savoy Hotel chef and bags of tweeds and guns.

Huntsmen they weren't, though. They were MI6 sizing up Bletchley Park as a base. A little more than a year later, they were back. Code-breaking was to begin.

The Germans used a code they changed every day, devised by settings on an elaborate typewriter that could change one letter for another with thousands of variations. Despite that, the Poles and the French broke Enigma before the war started. The Poles even captured an Enigma machine. But then both Poland and France were invaded and the codebreakers fled, turning up in London.

Things became tougher when the Germans added more keys, giving 159 million million million possible settings. Despite that it could be broken, because some messages were predictable: weather reports of clouds and wind speeds were betrayed by their numbers, and many messages ended "Heil Hitler!"

The trouble was that there were so many messages and no way to distinguish "We're running short of potatoes" from "We bomb Coventry tomorrow." By the time the code was broken, the bombing had happened or the potatoes had been delivered.

What was needed was a machine to whirr and rotate through the combinations until it found one that matched. From that, if the machine was right, the rest of the message, and all the day's messages, could be deciphered letter for letter.

The Bombe computer, rebuilt by enthusiasts

Inside the first computer. It couldn't decode messages, only work out what the code might be

The film, The Imitation Game, is notable for being accurate only to the extent that there was a place called Bletchley Park and a man called Alan Turing. Neither he or any mathematician built the code-breaking machine. Nor was it in a baronial hall; it was in a depressing, single-storey hut of the sort loved by armies everywhere.

Far from being in a baronial hall, Turing's computer was in a hut like this

And Turing, far from a social nutcase, was outgoing with a good sense of humour, although with a laugh to tax even his closest friends.

Odd, yes, but not in the way the film showed him.

The film didn't show the rest of the story. Doing the job really fast demanded an electronic computer. There was no such thing on the face of the earth and many doubted there would be. The job of thinking one up went to a man called Tommy Flowers, in the Post Office electronic labs in north London. His employers showed so little faith that he had to pay himself for some of what he needed.

Churchill on the library shelf. But he had the computers destroyed

It was he who created the world's first programmable electronic computer, although you'd never know it because Churchill had almost all the computers, manual and electronic, destroyed after the war for fear the Russians would copy them. Russia was the new enemy. The survivors went to the government eavesdropping centre at Cheltenham.

Flowers wanted to build computers after the war as well but no bank would lend him the money for such a preposterous idea. Secrecy forbade him from saying he had already made one. And so he slid out of history, a man who changed the course of the war but was awarded small change by an ungrateful nation.

When he was about 80, his children gave him a laptop computer. He couldn't work it. In his day, computers filled a room. He went to an evening class to learn, a stooped, white-haired man among the teenagers and housewives. They knew him as Tom.

Then one day somebody looked in the class register, someone who knew a little about computers.

"You're not the Thomas Flowers, by any chance?"

Cipher clerks dispatching messages; many had no idea until long after the war what they had been doing

Today's ride: 32 km (20 miles)
Total: 987 km (613 miles)

Rate this entry's writing	Heart	2
Comment on this entry	Comment	0