Donald Trump is determined to ensure that a corner of one of London’s biggest parks remains forever America.

The 99-year Crown Estate lease on Winfield House, the Regent’s Park residence of the US ambassador, is due to expire in 2053 and well-placed sources said the president is maneuvering to extend it.

The neo-Georgian mansion is unlikely to reach the open market, but property experts believe it could comfortably exceed the highest sale price on record for a house in London.

Earlier this year a Hong Kong billionaire, Cheung Chung-kiu, paid $274 million for a 45-room mansion in Knightsbridge. Winfield House boasts only 35 rooms, but its 12.5-acre garden is the second largest in London after Buckingham Palace and it comes with a star-studded history of famous owners, visiting presidents and dramatic encounters.

Trump, waiting to give Prince Charles a warm, sincere welcome to Winfield House.

Trump was a New York-based property developer before he became president in 2016. As his first term runs out, he is said to be personally lobbying for the Queen’s consent to a new deal on the ambassadorial residence.

He is understood to be hoping for either a transfer of the Crown Estate’s freehold, or an extension of the lease to 999 years. Trump is expected to raise the Winfield House lease as part of the negotiations for a US-UK trade deal, which he is prepared to accelerate if he wins a second term in next month’s election.

Winfield House boasts only 35 rooms, but its 12.5-acre garden is the second largest in London after Buckingham Palace and it comes with a star-studded history of famous owners, visiting presidents and dramatic encounters.

Woody Johnson, the US ambassador to London and a billionaire friend of Trump’s, recently raised the lease at a meeting with UK officials, according to a source who was present.

“Johnson could talk of little else,” the source said. “He said the president had taken a personal interest in [the residence] and was willing to use it as a bargaining chip in the forthcoming trade deal negotiations.”

Behind the president’s unusual intervention stands a grade II listed redbrick townhouse that more than makes up for its comparative lack of architectural distinction by occupying one of the finest sites in the capital.

Melania Trump; Suzanne Ircha, wife of the U.S. ambassador to the U.K.; and the Duchess of Cornwall practice their smiles at Winfield House last year.

The house is surrounded by vast expanses of lawn and woodland that was once said to be part of a “great forest, with wooded glades and lairs of wild beasts, deer both red and fallow, wild bulls and boars”. It also boasts tennis courts where Boris Johnson played in June as he recovered from his brush with the coronavirus.

The house was built in 1936-7 for the American heiress Barbara Hutton, the granddaughter of Frank Winfield Woolworth, the founder of the Woolworth shopping chain. Her seven husbands included the Hollywood actor Cary Grant, who visited the house twice before the couple divorced in 1945.

Hutton had barely finished furnishing her new home when war broke out and she returned home to America, where she was dubbed a “poor little rich girl” for her mostly unhappy private life.

Winfield House was then commandeered by the RAF for a barrage balloon unit. When Hutton returned to it, in 1946, she took one look inside and decided she could no longer live there. In an act of singular generosity, she offered to sell her lease on the entire estate to the US government for a token $1, an offer the president, Harry Truman, gratefully accepted.

Winfield House in 1938, after Barbara Hutton, the heiress to the Woolworth fortune, completed its construction.

The house, which has a helipad, became the US ambassador’s official residence in 1955 and often accommodates visiting presidents. It was where George HW Bush met the Soviet Union’s last leader, Mikhail Gorbachev, during the 1991 G7 summit.

Ronald Reagan was a frequent visitor and Senator George Mitchell hosted participants in the Northern Ireland peace process there during his review of the Good Friday agreement in November 1999. Barack Obama hosted a reception there for the Queen and Prince Philip.

The place has rarely attracted controversy, but America’s property holdings in London triggered a Trumpian tumult after the president took aim at the new purpose-built US embassy, with state-of-the-art security defences, overlooking the Thames in Nine Elms, south London.

Trump complained that Obama had sold America’s previous embassy in Mayfair’s Grosvenor Square for “peanuts” — $410 million — and replaced it with a new one on the wrong side of the river, although in fact the decision was made by George W Bush. The move was intended to improve security after the 9/11 attacks, but Trump claimed America had got a raw deal and a “horrible location”. He refused to attend the opening ceremonies in 2018.

Winfield House, surrounded by the Regent’s Park.

Winfield House appears to be more to Trump’s taste. Historic England’s description of the residence refers to “an entrance hall with neo-Adam plasterwork”; a reception hall entered via a “screen of paired fluted Doric columns”; “pilasters with Doric entablatures”; and “pedimented doorcases to walls”.

Other features include Chinese wallpaper, a Rococo carved chimney piece, 18th-century French boiseries and a “state dining room with fine 18th-century French Rococo overdoor reliefs alongside later plasterwork”.

Trump stayed at Winfield House during his state visit to Britain in June and hosted a black-tie dinner for prominent guests including Prince Charles and the Duchess of Cornwall. His enthusiasm for the house may be due in part to gilded decor reminiscent of his penthouse in Trump Tower, New York, but plans to extend the lease are understood to have the support of both Republicans and Democrats.

A source close to Liz Truss, the international trade secretary, who is leading the talks with America, said the subject had not been formally raised. Mike Pompeo, the US secretary of state, is expected to lead a trade delegation to the UK early next month.

A spokesman for the US embassy said: “Winfield House is an important symbol of the historic and enduring bond between the United Kingdom and the United States. Since the Second World War, it has hosted numerous leaders from our two countries and a wide range of British citizens from all walks of life.”

The spokesman added: “We do not comment publicly on negotiations concerning overseas leases. We look forward to honoring and continuing the long-standing traditions of Winfield House as the official residence of the United States ambassador to the Court of St James’s.”