Kirsty Bertarelli is Britain's richest woman and might be the country's worst neighbour

Meet Kirsty Bertarelli. She's probably the worst neighbour to have in Britain. She also happens to be the richest woman in the UK too.

Her fortune is so large that she is worth more than Harry Potter author JK Rowling and the Queen combined at £9.75 billion ($14.5 billion), according to the Sunday Times Rich List 2014.

But the singer, former Miss UK and wife of Switzerland's richest man Ernesto Bertarelli, after he sold his family's pharmaceuticals firm Serono for £9 billion to Merck, is set to cause a massive, literal headache for her neighbours.

The 43 year old just won planning permission from Westminster Council to build a £10 million "mega basement" underneath her £5.5 million house on one of London's wealthiest streets. [The British press cannot identify the exact location of the Bertarellis' house under privacy laws.]

What she plans to do is to turn her mews house, which she shares with her husband and three children, into an "iceberg," as the basement will be two storeys deep. Effectively, she's turning her basement into a secret underground lair that any evil genius from a Bond movie would be proud of.

According to sketches by the couple's architects, Boundary Space, the basement will host a family room, cinema another kitchen, dining room and gym.

"There have been a large number of objections from other residents within the mews," said John Walker, Westminster City Council's operational director of development planning, in a report cited by the Telegraph.

"Concern has been raised by residents that the use of the basements has not been specified, and that they might be used as recording studios. They are concerned that the excavation of new basements is a risky construction process, with potential harm to the property and adjoining buildings."

However, despite Westminster Council banning "iceberg" developments by end of this year, it approved the application.

As the Telegraph pointed out, if the Bertarellis only live a few streets away from Kensington and Chelsea council, which has "already banned 'excessive' two-storey 'iceberg' extensions, which it says are unacceptably disruptive to neighbours."