Nearly 100 scientists have written an open letter to The Times calling for Bletchley Park to be preserved for the nation.

Home to the first programmable computers during the Second World War and the location of much of the code breaking activity that did so much to shorten the conflict, Bletchley Park falling into disrepair and urgent action is needed.

"As a nation we cannot allow this crucial and unique piece of British and world heritage to be neglected in this way," the letter reads.

"The future of the site, buildings, resources and equipment at Bletchley Park must be preserved for future generations."

Operations at Bletchley Park were set up in the first year of the war to crack German and later Japanese encryption systems.

Its staff included such legendary figures as Dr Alan Turing and Dr Tommy Flowers, who built the Colossus computer.

The unit was disbanded after the war, and the site was cleared on Churchill's orders after he grew concerned that the Russians would realise how advanced the code breaking operation had become.

Almost all of its staff never spoke about their wartime role until the details were declassified in the late 1980s. Key staff were also neglected, like Turing who committed suicide after being convicted of homosexuality.

"He was a funny old bird," a former secretary at the site told vnunet.com some years ago. "We didn't talk about the work we were doing there, but we knew it was important."

The scientists want money to be spent on restoring the historic site which, while open to the public, receives no public funding. A plan has been mooted to house a national computing museum at the site but funds are short.

"I don't think people realise what a state it's in, despite the best efforts of the people looking after it," said Sue Black, head of the Department of Information and Software Systems at the University of Westminster.

"If we don't do something now we're going to lose what's left. If we leave it 10 years it might be too late."