The Government is led by the Prime Minister, who selects all the remaining Ministers. The Prime Minister and the other most senior Ministers belong to the supreme decision-making committee, known as the Cabinet. The Government Ministers are all members of Parliament, and are accountable to it. The Government is dependent on Parliament to make primary legislation, which means that in practice a government must seek re-election at least every five years. The monarch selects the Prime Minister as the leader of the party most likely to command a majority in Parliament.

     Under the unwritten British constitution, executive authority lies with the monarch, although this authority is exercised only by, or on the advice of, the Prime Minister and the Cabinet. The Cabinet members advise the monarch as members of the Privy Council. They also exercise power directly as leaders of the Government Departments.

     The current Prime Minister is David Cameron, leader of the Conservative Party, who was appointed by Queen Elizabeth II on 11 May 2010 following the General Election on 6 May 2010. The election failed to provide a decisive result, with the Conservatives as the biggest party within a hung parliament. A coalition government was formed on the 12 May between the Conservatives and the Liberal Democrats (see Cameron ministry).