Runnymede Borough Council issued a planning enforcement notice for the Windsor Park Hotel in Egham last month after an extra wing was installed and the building was extended without planning permission.

Surinder Arora, a Tory donor who owns the facility, has been told to demolish all or part of the building.

He has until October 7 to appeal.

The council said it was “disappointed” that the works were done without permission.

The Fairmont Windsor Park Hotel hosted the signing of the Windsor Framework in February, where Rishi Sunak and Ursula von der Leyen agreed on post-Brexit trading arrangements for Northern Ireland.

The Times reported the council considered the hotel to have a “harmful effect on the green belt”.

In a statement, Mr Arora said: “We are truly sorry for the mistakes made during the construction of the Fairmont Windsor Park.

“It was a highly challenging construction site being developed in the middle of the Covid-19 pandemic. We are now constructively engaging with Runnymede Council and other local stakeholders to find mutually acceptable solutions to the planning concerns.”