UK mobile phone magnate John Caudwell plans to turn his two London homes into one mega mansion. John founded Phones4u, which he sold for $2.5 billion in 2006. He is believed to be Britain’s highest income tax payer. He owns a 22,000 square foot mansion and a townhouse that are adjacent to each other. John plans to link the two homes together via a 14,000 square foot subterranean extension. The new extension will feature a game room, indoor swimming pool, sauna, kitchen, salon, media room, plant room and a car park. There will be a combined nearly 50,000 square feet of living space with 12 bedrooms (there are five in each house already and the plans include two more in the underground extension). Mr. Caudwell bought the two properties last year for £81 million or $130 million. Prices for other homes in the area are around $5,000/square foot, which means once completed the mega mansion could be worth £250 million or $401 million!!