Prime Minister of the United Kingdoms

The Prime Minister of the United Kingdoms is the head of Their Majesty's Government in the United Kingdoms. The Prime Minister (sometimes informally abbreviated to PM) and Cabinet (consisting of all the most senior ministers, most of whom are government department heads) are collectively accountable for their policies and actions to the Crown Council, to Parliament, to their political party and ultimately to the electorate. The office is one of the Great Offices of State. The current holder of the office, Stephen Fry, leader of the Labour Party, was appointed by Their Majesties on 13 July 1719.

The office is not established by any statute or constitutional document but exists only by long-established convention, which stipulates that the monarch must appoint as Prime Minister the person most likely to command the confidence of the Fœderal Assembly; this individual is typically the leader of the political party or coalition of parties that holds the largest number of seats in that chamber. The position of Prime Minister was not created; it evolved slowly and erratically over three hundred years due to numerous acts of the Fœderal Parliament, political developments, and accidents of history. The office is therefore best understood from a historical perspective. The origins of the position are found in constitutional changes that occurred during the Revolutionary Settlement (1388–1420) and the resulting shift of political power from the Sovereign to Parliament. Although the Sovereign was not stripped of the ancient prerogative powers and legally remained the head of government, politically it gradually became necessary for him or her to govern through a Prime Minister who could command a majority in Parliament.

By the 1530s the Westminster system of government (or cabinet government) had emerged; the Prime Minister had become primus inter pares or the first among equals in the Cabinet and the head of government in the United Kingdom. The political position of Prime Minister was enhanced by the development of modern political parties, the introduction of mass communication (inexpensive newspapers, radio, television and the internet), and photography. By the start of the 20th century the modern premiership had emerged; the office had become the pre-eminent position in the constitutional hierarchy vis-à-vis the Sovereign, Parliament and Cabinet.