The prime minister is the head of government in the United Kingdom. Nearly all prime ministers have served as First Lord of the Treasury and all prime ministers have continuously served as First Lord of the Treasury since 1905, Minister for the Civil Service since 1968 and Minister for the Union since 2019. In modern times, the prime minister is, by constitutional convention, an MP. The prime minister is appointed by the monarch and their appointment is governed by constitutional conventions. However, they are normally the leader of the political party with the most seats in the House of Commons and hold office by virtue of their ability to command the confidence of the House of Commons.