Bletchley Park, the codebreaking centre that helped to win the Second World War and launch the modern computer, is in danger of irreparable decay unless the Government steps in to save it, some of the country’s leading computer scientists caution today.

In a letter to The Times, 97 senior experts, mostly professors and heads of department, say that “the ravages of age and a lack of investment” have left the historic site under threat.

One of the unheated wooden huts where the codebreakers worked day and night to turn the tide of the war now looks “like a garden shed that’s been left for 60 years”, according to Sue Black, head of the Department of Information and Software Systems at the University of Westminster and one of the organisers of the letter.

A dirty tarpaulin keeps out the rain, and several of the eight surviving huts have peeling paint and boarded-up windows.

Times Archive, 1977: Bletchley Park secrets revealed

Codebreakers were regularly cracking Enigma from the spring of 1940 using the earliest computers ever to be built

• Scharnhorst dash aided by decoding failure

• Enigma disclosures

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Time was running out, she said. “If we don’t do something now we’re going to lose what’s left. If we leave it ten years it might be too late.”

The signatories call for Bletchley Park to be made the home of a national museum of computing. Bletchley is open to the public as a museum but receives no public funds and the signatories say that many of the huts where the codebreaking occurred are in a terrible state of repair.

“As a nation we cannot allow this crucial and unique piece of both British and world heritage to be neglected in this way. The future of the site, buildings, resources and equipment at Bletchley Park must be preserved for future generations,” they say. Dr Black said yesterday that the site “is fundamental for the history of computing because we wouldn’t have the computers we’ve got now without it, and fundamental for our history because we might not have won the war without it”. Bletchley, a Victorian mansion in what was then the Buckinghamshire countryside, was an unlikely place for such an achievement. But it was there that the Government Code and Cipher School arrived in 1939, masquerading as Captain Ridley’s Shooting Party.

Its mathematicians, led by the erratically brilliant Alan Turing, managed to crack the brain-achingly complex Engima codes, which the Germans thought were unbreakable. The intelligence that this generated saved countless Allied lives and may have shortened the war significantly.As the German ciphers became ever more elaborate, the codebreakers fought back, and their efforts culminated in the Colossus, one of the world’s first programmable electronic computers. It was an advance that kick-started modern British computing.

After the war Churchill destroyed all evidence of the codebreaking programme, desperate that the Soviet Union should not discover it. He called the workers of Bletchley “the geese that laid the golden egg and never cackled”. Everyone who worked there, from codebreaker to tea-maker, was forbidden to talk about the work. Many never told their families.

The secrecy meant that few realised Bletchley’s importance. For the next 40 years the site became a government training school and in 1991 it was decided to raze the ramshackle buildings and put up a housing development.

The next year the Bletchley Park Trust was formed to save the site, bringing together historians and ex-codebreakers, and eventually succeeded in opening it to the public.

As the codebreaking programme was gradually declassified, the Bletchley story became much better known, helped by Robert Harris’s bestselling book Enigma, which was made into a film with Kate Winslet. Yet a lack of funds has left the site in crumbling disrepair.

“I don’t think people realise what a state it’s in, despite the best efforts of the people looking after it,” Dr Black said.

Secret services

— Bletchley Park was also known as Station X, because it was the tenth such station to be opened

— It is a museum open to the public. The manor house is licensed for weddings

— The estate was formerly part of the Manor of Eaton, included in the Domesday Book

— It was on the “Varsity Line” railway between Oxford and Cambridge universities, which supplied many codebreakers

— The Government Code and Cipher School began moving to Bletchley on August 15, 1939

— Listening stations (the Y-stations) gathered signals for processing at Bletchley, but it was only in the 1970s that the work was revealed to the public

— GCHQ ended training courses at Bletchley in 1987

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