Former Station X worker Lady Bobby Hooper: "There's lots of Churchill memorabilia and a beautiful park"

Campaigners had feared that the Buckinghamshire mansion, formerly known only as Station X, was going to be sold to property developers.

The 55-acre site, which currently houses a small museum and offers guided tours, has planning permission and is worth millions of pounds.

Enigma decryption teams worked round the clock, in top secrecy

But Bletchley Park Trust, which runs the park, is negotiating a deal with joint owners, government land agency Pace and British Telecom, to secure it under its control.

An announcement detailing the deal is expected to be made next week.

The trust plans to turn the site into a world-class theme park which it describes as a "living memorial to Second World War intelligence work, computing and cryptology".

The trust says it needs £1.5m for its plans - which would also include a conference centre and facilities for local people and industry - and has approached US computer billionaire Bill Gates for sponsorship.

Bill Gates: Approached for the £1.5m required

His response has yet to be made public, but Robert Harris, who immortalised the Bletchley Park story in his best-selling novel Enigma, says Mr Gates would be an ideal sponsor.

"Without the work - and the genius - of many of the people there he would certainly not have become anything like as fabulously wealthy as he is today," he said in a newspaper interview.

He added that he was "delighted" that Bletchley had been saved. "It has been a long battle - longer in fact than World War II," he said.

'Golden egg'

During World War II, Bletchley Park was home to a secret group of mathematicians, crossword experts and intelligence officers who used early computers to break the codes in which German U-boats communicated.

The public knew nothing of the site's existence until the 1980s, with the declassification of government papers.

Its work and secrecy led to Britain's wartime leader Winston Churchill commenting that Bletchley Park "was the goose that laid the golden egg but never cackled".

Its story is currently being turned into a £90m Hollywood blockbuster starring Harvey Keitel and Jon Bon Jovi.