The United Kingdom is home to over 177 Billionaires with a combined net worth of £653 billion pounds, today we look at ten of them. — 10 — Mayfair Mega Mansion — John Caudwell Considered to be Britain’s most expensive home in Mayfair, this impressive home is thought to have cost Phones4U founder John Caudwell £250 million pounds. Having around 15 bedrooms, a mirrored dancefloor, basement nightclub five kitchens and a 120-capacity ballroom, the home covers 43,000 square feet.