Inside Britain's most expensive home – valued at £250 million

Phones 4u founder John Caudwell has turned two mega-mansions in Mayfair into one vast property that, with an estimated value of £250 million, is thought to be Britain's most expensive private home.

• See inside one of London's most expensive houses – the modern mansion worth £40m

Businessman and philanthropist Caudwell, who sold his Phones 4u chain for just under £1.5 billion in 2006, bought Mayfair House for £87 million in 2012 and a few years later embarked on a total renovation.

It was also the subject of a Channel 4 show, which aired earlier in the year, ‘Britain’s Most Expensive Home: Building for a Billionaire’ that has been described as a 'supersize Grand Designs' – that spiralled £58 million over budget.

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Britain’s most expensive mansion, in central London, isn’t even John Caudwell’s main home. Rather, it’s a party retreat for his wealthy investors.

The home features a 120-capacity ballroom – a place for charity balls and evening galas.

The house is the most expensive in the UK firstly, because it is so enormous, 43,000 sq ft of living space in total and secondly, as a result of the quite staggering levels of eccentric opulence and design details that has gone into the renovation.

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The property features an indoor river (below), designed to be evocative of Thailand, that meanders out from a faux cherry tree, and rungs through the house.

Then there’s the quilted, soundproofed cinema room decorated with black-and-white photographs of Hollywood stars with the faces of John Caudwell’s family superimposed.

‘The value in my house is the house itself, but I don’t keep any valuables. You can’t steal a marble staircase,’ John explained.

The home can be seen it all its glory on Channel 4.