11 Downing Street (commonly known as Number 11), is the official residence of Britain's Second Lord of the Treasury who is formally recognised as the Chancellor of the Exchequer.The first Chancellor to live there was Henry Petty-Fitzmaurice in 1806, but Number 11 did not become the Chancellor's official residence until 1828.It is currently the official residence of George Osborne, who was appointed as Chancellor by Prime Minister David Cameron on 11 May 2010.