Prime Minister of the United Kingdom century as a convention of the constitution, the position of Leader of the Opposition was given statutory recognition in 1937 by the Ministers of the Crown Act. British Prime Ministers have never been elected directly by the public. A Prime Minister need not be a party leader; David Lloyd George was not a party leader during his service as prime Minister during World War I, and neither was Ramsay MacDonald from 1931 to 1935. Prime Ministers have taken office because they were members of either the Commons or Lords, and either inherited a majority in the Commons or won more
Acting prime minister is on vacation, or is in ill health. In the early 20th century, when travel by ship was still the norm, it was not uncommon for there to be an acting Prime Minister for months on end. The deputy Prime Minister is usually designated as the acting Prime Minister, although another senior member of the government may fill the role if both the Prime Minister and deputy Prime Minister are unavailable. An acting Prime Minister is required quite frequently – for instance, between 3 December 2007 and 23 February 2009 (during Kevin Rudd's first term), Julia Gillard acted as Prime