<P> Downing Street is a street in London that houses the official residences and offices of the Prime Minister of the United Kingdom and the Chancellor of the Exchequer . Situated in Whitehall, a few minutes' walk from the Houses of Parliament, Downing Street was built in the 1680s by Sir George Downing . </P> <P> For more than three hundred years, it has held the official residences of both the First Lord of the Treasury, the office now synonymous with that of the Prime Minister, and the Second Lord of the Treasury, the office held by the Chancellor of the Exchequer . </P> <P> The Prime Minister's official residence is 10 Downing Street; the Chancellor's official residence is Number 11 . The government's Chief Whip has an official residence at Number 12 . The current Chief Whip's residence is at Number 9 . The houses on the south side of the street were demolished in the 19th century to make way for government offices now occupied by the Foreign and Commonwealth Office . </P> <P> "Downing Street" is used as a metonym for the Government of the United Kingdom . </P>

Who lives next door to number 10 downing street