Downing Street in London, England, has for more than three hundred years housed the official residences of two of the most senior British Cabinet ministers: the First Lord of the Treasury, an office now synonymous with that of Prime Minister of the United Kingdom; and the Second Lord of the Treasury, an office held by the Chancellor of the Exchequer. The Prime Minister's official residence is 10 Downing Street; the Chancellor's official residence is next door at Number 11. The Government's Chief Whip has an official residence at Number 12, though the current Chief Whip's residence is at Number 9.