Britain's wealthiest woman Kirsty Bertarelli has upset neighbours with plans to build a two-storey mega basement beneath her £10m Westminster home.
The former Miss UK, whose husband's family are worth an estimated £9.75bn, was given the green light to convert their mews into an "iceberg" home.
The three-storey terrace is in Belgravia, one of the country's most expensive districts.
Mrs Bertarelli, 43, is married to Swiss-Italian pharmaceuticals magnate Ernesto Bertarelli.
The couple plan to double the size of the home they bought for £5.5m 13 years ago.
The upgrade will turn it into a "modern family home with appropriate facilities".
Plans submitted by architects add: "The proposals reflect the client's family has grown, and the accommodation is no longer conducive to modern family living."
Yet the decision by Westminster Council to approve the three-year project has left neighbours furious.
Of around a dozen homes on the street it will be the third to see major groundworks and rebuilding in recent years.
The narrow cobbled road that runs between the homes, originally built to house servants in adjoining mansions, means residents will have to compete with heavy vehicles throughout the works.
One neighbour, who did not wish to be named, said: "Some of the owners around here are absolutely apoplectic about what's in the pipeline.
"These kinds of developments cause huge disruption.
"In the last few years there has already been one double basement conversion and a single basement. There will be hardly any earth left eventually.
"The houses were never intended to be enormous family homes and the street is just about wide enough to fit two cars down it side-by-side.
"All the traffic will have to come through one archway and if that's destroyed we will be devastated.
"The family have lived here for over a decade but they probably spend around six weeks maximum here a year.
"It's like we have rock stars coming to stay when they arrive, there's an army of drivers and minders for the kids, it's mayhem.
"They are obviously going to spend a huge amount on a place they hardly live in, it's staggering. But then the richest are oblivious to how your regular people live and we will have to deal with the consequences.
"But there aren't many Mr and Mrs Joneses on the Mews. The owners are from all sorts of countries."
One longstanding resident of the street, who also wanted to remain anonymous, said: "We all went to a meeting at Westminster Council two nights ago.
"It's been approved, there's obviously been a great deal of objection to the plans because of the noise and site traffic, sadly it's one of those things we will have to live with.
"It is going to be a major development, these streets are simply not designed for such huge projects and some of these buildings date back to 1840.
"We put our objections to the council beforehand and crossed our fingers. Mr Bertarelli has a pretty penny, but it came down to having to watch a group of planners discuss it, we couldn't say a thing.
"As far as I know the Mr and Mrs Bertarelli weren't there.
"This is going to be a three-year project, they are going to completely gut the building and dig down, I have no idea how that's going to be done without seriously disrupting us and affecting our day-to-day lives.
"One of the annoying things is Kensington and Chelsea have banned these developments, we don't know why Westminster hasn't done so.
"You are talking about completely different rules for developments with exactly the same problems.
"But if there isn't a law against it they are within their rights to go ahead and try."
Nobody was at the Bertarelli's home for comment.
Originally published on Mirror Online.