A museum paying tribute to Jewish refugees who performed a crucial intelligence role in the Second World War is a step closer to reality.

Backers of the Trent Park Museum Trust have signed a legal agreement with property developers which could see the museum open by 2020.

Trent Park mansion, at the heart of a sprawling country park in Enfield, north London, was used as a prisoner of war camp for 59 senior Nazi generals — including Hitler’s deputy Rudolf Hess.

Their conversations about the Final Solution, Hitler’s atomic bomb programme and U-boat tactics were secretly monitored by 103 Jewish refugees from the Nazis recruited by MI6 because they were fluent in German.

The listeners received no acknowledgement of their work. Just two are still alive: Eric Mark, who lives in Belgium, and Fritz Lustig, from north London.

Last week an agreement was signed between historian Dr Helen Fry, Jason Charalambous, chairman of Trent Park Museum Trust, and the Berkeley Group, which intends to convert the mansion into housing.

The plans must still be approved by Enfield Council, but they ensure the ground floor and basement of the grade II listed property will be leased to the trust. Once approval is granted, millions of pounds must be raised.

As well as learning about the estate’s wartime past, visitors will discover its earlier history. As the home of Sir Philip Sassoon from 1912 to 1939, it was a socialite’s paradise, regularly hosting figures such as Charlie Chaplin, Winston Churchill and even the Queen.

Dr Fry told the JC: “We are delighted that Berkley has guaranteed the future of the museum.

“It is obviously important for Jewish history and Holocaust education, but is a site of national importance as well. In March 1943, it was discovered at Trent Park that Hitler had a secret site in north Germany where they were developing the V1 and V2 rockets.”

Mr Charalambous, who initiated the campaign, said: “We have got a long way to go, but everything seems to be falling in to place.”