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
Prime minister could command the loyalty of the Commons was increasingly necessary. The long tenure of the wartime prime minister William Pitt the Younger (1783–1801), combined with the mental illness of George III, consolidated the power of the post. The title was first referred to on government documents during the administration of Benjamin Disraeli but did not appear in the formal British Order of precedence until 1905. The prestige of British institutions in the 19th century and the growth of the British Empire saw the British model of cabinet government, headed by a prime minister, widely copied, both in other European countries