HOLLYWOOD A-list actor Jude Law plans to build a subterranean gym in what is believed to be the first ever basement excavation on a much-loved historic Highgate street.

Law submitted a detailed planning application to Camden Council under his real name David Law, showcasing plans to make the recently refurbished house look older by returning his �8million Georgian mansion “to its original splendour”.

But Michael Hammerson, a member of the Highgate Society, has expressed concern that the worrying precedent of basement excavations has spread to one of Highgate’s most architecturally precious streets – which the Ham&High cannot name for privacy reasons.

He said: “We have the same reservations about this development as we do about all the other basement excavations around Hampstead and Highgate, the accumulation of which is going to be very damaging.

“This is first basement excavation that we have had on this street, although that house is not Grade II*-listed Camden has to be firm on this and make sure they know what effect such a large excavation underneath the house’s back terrace will have on neighbouring gardens and houses as they can be seriously damaging.”

There is already a basement at Mr Law’s property but there are plans to extend this by excavating under the back garden terrace for the entire width of the house to create a “lightwell” and gym area. The house is part of a terrace so the basement extension will reach the property lines of the plot of land.

The plans also reveal that Law wants to create a sunken garden next to the new gym and to add solar panels to the roof. A new dormer window, a new roof window and a new balcony will also be added to the 1832 property.

The building will also boast a wine cellar, bike storage, two studies and a meeting room in the eves.

Although the house was largely rebuilt between 2000 and 2001 and does not have the Grade II* listing that many of the other houses on the street have been given, it is still Grade II-listed.

The plans include removing a staircase installed in 2001, removing ‘modern’ doors and renovating the fireplaces. Law’s architects, Richard Keep, claim the changes are justified as the current design ‘does not reflect the original layout’ of the building.

Mr Hammerson also said that the society was encouraging anyone building in the area – including the exclusive Highgate School which is building in the North Road area – to undertake historical excavation as part of any works.

Mr Hammerson continued: “The area Mr Law will be digging will have fairly significant archaeological implications for the local area, some of those houses date from the early 18th century and there may well be valuable archaeological information from that period or even earlier dates. It is important that we preserve that history.

“There is of course an open invitation to Mr Law to come and talk to the society about our concerns.”

Law’s architect Richard Keep said that this excavation was not be as intrusive as many others as there is already an existing basement to the property and the plans simply involve extending this under the terrace.

He said he would prefer not to comment further as the plans would go out to consultation and all views would be heard then.