Keeping up with the Joneskys

A new conservatory ...some decking in the back garden ...perhaps an attic conversion to have an extra room for the kids ...well for some of us that will be a worth-while achievement , but for the capitalist class , its underground tennis courts and three story car parks .

The Times reports that with 15 bedrooms, vast entertaining suites and exquisite plasterwork, 15 Kensington Palace Gardens was one of the most expensive – and exclusive – houses ever to have changed hands in London when it was bought by Leonard Blavatnik, a Russian-born oil tycoon, for £41m in 2004. Yet all that opulence is clearly not enough for Blavatnik . According to plans submitted this summer to Kensington and Chelsea council, the tycoon, who has relocated to London, is seeking permission to excavate under the garden, to the front and rear of the sprawling pile, making space for a three-storey garage with car stacker, a swimming pool, a gym and a private home cinema.

Russian oligarchs, private-equity traders and hedge-fund managers are engaged in a multimillion-pound game of one-upmanship as they vie with each other to dig ever bigger, wider and deeper extensions. Behind the white stucco fronts and redbrick exteriors of Belgravia and Chelsea, London’s super-rich are digging down and building outwards and upwards .

The latest must-have feature is an adjustable-height swimming pool. At the flick of a button – because everything is remote-controlled – the bottom can be raised or lowered by a giant hydraulic jack, forming a deep swimming pool for the heavyweight millionaire or a toddler-friendly paddling pool for his offspring. Optional extras include a retractable glass roof or a discreet cover that will slide over the pool, creating a ballroom or banqueting hall. It doesn’t have to be modern or minimal – one house in Mayfair has a Roman-style pool, complete with columns.

“London is awash with money,” says Robin Ellis , known in the trade as “London’s poshest builder”, “Vast tracts of London are being dug up to create sub-basements,” he adds. “My clients are prepared to pay to create houses that push all the boundaries of luxury and technology. I’ve put in a swimming pool with a cover that rose, concertina-style, up and over the water to convert the space into a private concert hall, with seating for 100.”

It is all reminiscent of the mercantile extravagance of 15th-century Venice or the wild opulence of the reign of Louis XIV. London now has more billionaires then anywhere else in the world after New York and Moscow .

Few can compete with Chris Rokos, a secretive hedge-fund tycoon. The lavish plans for his eight-bedroom house in Notting Hill, submitted to the planners this month, include a gym, a home cinema, library, a third-floor open-air pool, an internal climbing wall, a subterranean garage with motorised lift for two cars and an 80ft-tall glass atrium. As if that’s not enough, Rokos, 36, plans to dig four storeys below ground to create a 16ft-deep swimming pool with high board.

“When they go round the houses of all of their mates who have done something, they want to do it better – money is no object,” says Jonathan Hewlett, head of London sales at Savills estate agency.

For example, Gibson Music, multi-audio specialists who have been hard-wiring homes for more than 20 years, have just put in £250,000 worth of technology by Creston, which specialises in top-of-the-range control systems. Other extravagant features recently demanded by clients include a vanity unit for 2,100 lipsticks; a glass-fronted, temperature-controlled wine cellar, complete with fibreoptic lighting and carved macassar ebony shelves, to hold 4,000 bottles; walk-in showers with waterproof television screens and glass walls that turn opaque with the press of a button, and cost £1,000 per square metre.

And there was some of us thinking we would be the bees knees with a 42-inch plasma screen tv , too