In central London, on land the size of seven football pitches, sits a mansion called Winfield House - the official residence of the US ambassador to the UK.

It may be a stately home but through the years it's been known to throw one hell of a party, especially on 4 July, America's Independence Day. This year's celebration saw Nile Rodgers & Chic headline the building's lawn for thousands of people.

Fashion's elite, sports stars and wartime leaders have all been entertained here. Even in 1825 when the original site was built, according to Winfield's official website, its primary use was for entertainment.

President Donald Trump has spent the first night of his state visit at the 35-room mansion. The Trumps also stayed there in 2019, as did the Bidens and Obamas previously.

"It's not just the home of the ambassador, but it's also a centre of diplomatic hospitality," says Stephen Crisp, formerly the property's head gardener, who worked there for 37 years until his retirement last year.

One thing Winfield isn't, is a tourist attraction. Located inside Regent's Park, it's exclusive and takes planning to get inside. Friends of Regent's Park previously arranged tours of the grounds - but so far this year the ambassador has not granted permission.

From the road outside, the house cannot be seen. It's shrouded in woodland and is very private for central London.

"It's really, really difficult to get in there. I regard it as a feather in my cap that I actually managed to get in," says Viv Ward, Friends of Regent's Park's event manager. He calls the house "magnificent" and is audibly in awe of the grounds.

Tours of Winfield only allow you to see the ground floor,........

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