The four-storey London mansion hidden almost entirely underground: 15 bedrooms, 7 bathrooms, 20 toilets, a ballroom, a pool... and neighbours in uproar

When it comes to building in Central London, land is like gold dust.
Below ground, though? That’s another story.
A multi-millionaire plans to triple the size of his mansion by digging down 50ft to create a four-storey basement complete with swimming pool, spa, ballroom and no fewer than 20 toilets.

The multi-millionaire will triple the size of his Knightsbridge mansion by extending beneath the ground

Wealthy residents are furious after seeing the planning proposals, pictured

Planning form: The excavation will feature a 14-metre swimming pool, hot tub, sauna, massage room, ballroom, covered courtyards, staff accommodation, parking for three vehicles, a turning circle and a car lift

Wealthy Canadian David Graham has plans to build a three-storey basement extension underneath the former magistrates' court turned home

Unluckily for David Graham – a former cable TV mogul – building under your home is no less controversial than extending it on the surface. His plans have caused fury among the well-heeled residents of Knightsbridge, including a novelist and a duchess.

Architects’ drawings show how the vast house, originally built as a school in the 19th century, will be created by excavating deeper than the height of neighbouring homes.

As well as the spa area, it will have servants’ quarters consisting of five staff bedrooms. There will also be wine cellars, an art storage room, parking for three vehicles and a car lift.

In total the house will have 15 bedrooms, seven bathrooms and 20 toilets. Rooms upstairs will include a library, bar, and laundry.

Estate agents estimate the property could be worth up to £90million with the work completed.

Novelist Edna O'Brien, left, who objects to the planning proposals by David Graham, and Mr Graham's former wife Barbara Amiel, right, who was married to disgraced media mogul Conrad Black

Big extension: Residents say only a few people were told about the planning proposals and they now only have a week to submit their objections

Neighbours say the massive excavation, which will involve 1,375 skipfuls of earth being removed, will bring years of ‘utter misery’. But Canadian Mr Graham says the extension is necessary to provide his ‘family’s needs as required by today’s contemporary living’.

The 75-year-old, who was once married to Barbara Amiel, wife of disgraced media mogul Conrad Black, bought the property in 2000 and converted it into a house.

He was granted permission to build a pool and one basement level, but now wants to add three additional storeys extending under the house and garden.

According to the application submitted to the Royal Borough of Kensington and Chelsea, Mr Graham ‘has been looking for a larger house in the locality which has proved unsuccessful.

He therefore wishes to extend his home to provide further accommodation for his family and servants’.

The firm that filed the application on his behalf said the conversion would take up to four years.

Neighbours who have objected to the plans include novelist Edna O’Brien and the Duchess of St Albans Gillian Beauclerk.

The duchess said: ‘These plans are absolutely monstrous and unnecessary. It’s just absolute greed.

No one needs that much space.’

A spokesman for the nearby Milner Street Area Residents Association said: ‘Why should we all suffer just so one man can indulge his fantasy?’

Mr Graham, who made hundreds of millions when he sold his cable TV business, could not be contacted for comment.

The plush property in Knightsbridge that could become a building site for four years

A view of the upmarket street in London where local businesses and residents are angry at the plans

Neighbours who have objected to the plans include novelist Edna O’Brien and the Duchess of St Albans Gillian Beauclerk.
The duchess said: ‘These plans are absolutely monstrous and unnecessary. It’s just absolute greed.

No one needs that much space.’

A spokesman for the nearby Milner Street Area Residents Association said: ‘Why should we all suffer just so one man can indulge his fantasy?’

Mr Graham, who made hundreds of millions when he sold his cable TV business, could not be contacted for comment.