The Prime Minister sold his Islington home for ?615,000 when he moved into Downing Street - only to see its value rocket when the market took off in the late Nineties. At the time, his profit of ?240,000 - he bought the house for ?375,000 in 1993, at a time when he was still eyeing the top job - seemed considerable. But, less than four years later, the couple who bought it sold it on for just under ?1.5million.