Bletchley hums again to the Turing Bombe

By Aussiegirl

I didn't know that these code-breaking machines had all been destroyed after WWII. Now there's a fully-fuctioning replica on display again.

Telegraph | News | Bletchley hums again to the Turing Bombe

Bletchley hums again to the Turing Bombe
By Ben Fenton

(The last time that the rattle of the Turing Bombe was heard, it was the greatest secret of the British Empire.

Former bombe operator Jean Valentine is reunited with a restored, fully-functioning machine at Bletchley Park and [inset] during the war
Yesterday, it was a press event.

With a rumble that turned into a roar, a sound not heard at Bletchley Park for more than half a century, the machine that was at the heart of Britain's wartime code-breaking triumph began to work again.

The operation of the bombe was likened by the men and, mostly, women who worked on it to a vast collection of knitting needles, but its sound was also the first hint of the computerised world in which we now live.

Yesterday, a fully-functioning recreation of the bombe was switched on for the first time, by re-enactors in period dress, bringing back to life the great-great uncle of the PC.

The bombe was the key to cracking the German code known as Enigma, which Hitler's regime believed unbreakable, and in doing so it helped to win the Battle of Britain in 1940 and the Battle of the Atlantic in 1942-43.

Developed by the mathematicians Alan Turing and Gordon Welchman, the first bombe was built by the British Tabulating Machine Company in Letchworth, Herts.

The first prototype was delivered to Bletchley, the secret code-breaking headquarters outside Milton Keynes, in March 1940, but it was not truly successful at cracking Enigma until a second version came into use about six months later.

All 200 of the bombes built for Bletchley were destroyed after the war, so cloaked in secrecy was the project.

So when John Harper, the leader of a team of engineers and mathematicians, decided that it was of great historical importance to have a working bombe available to the public for inspection, all he had to work with were blueprints from GCHQ – the modern equivalent of Bletchley – a few aged photographs and the memories of some elderly code-breakers.

But after 10 years, their success was finally and loudly advertised across the old headquarters yesterday.

The rebuilding project involved making almost everything involved from scratch and the engineers estimated that they had used 10 miles of wire alone in constructing the complex machinery.

Simon Greenish, the director of Bletchley Park Trust, said the reconstruction was an "astonishing achievement".

He said: "What was done at Bletchley has affected all our lives in one way or another because the Second World War would not have ended when it did if it wasn't for Bletchley."

Frank Carter, one of the mathematicians involved, said: "Without Bletchley the war could have lasted another two years. That would have meant atomic weapons in Europe, more and more devastating weapons and many, many more deaths.

That's why we believed it was necessary to have this machine available for schoolchildren, and adults, to see exactly what the contribution of this remarkable place was like."

The bombe worked not as a proto-computer – that was the role played by the later machine Colossus, also developed at Bletchley – but as an electro-mechanical machine that tried out all the possible combinations in which the German encoding machine Enigma could be set.

It did so at a speed which meant that the Bletchley team could read messages from German military and naval commanders, who assumed that Enigma was unbreakable, within nine hours.