The United Kingdom is a constitutional monarchy which, by legislation and convention, operates as a unitary parliamentary democracy. A hereditary monarch, currently King Charles III, serves as head of state while the prime minister of the United Kingdom, currently Sir Keir Starmer since 2024, serves as the head of the elected government.
Under the United Kingdom's parliamentary system, executive power is exercised by His Majesty's Government, whose prime minister is formally appointed by the king to act in his name. The king must appoint a member of parliament that can command the confidence of the House of Commons, usually the leader of the majority party or apparent majority party, though the king may choose to appoint an alternative if they say that they cannot expect the confidence of the House. Having taken office, the prime minister can then appoint all other ministers from parliament.