ProjectsLibraryNotice BoardAbout UsContact Us
  Economic & Social Research Council Website
Prime Minister of the United Kingdom

The Prime Minister of the United Kingdom (informally abbreviated to PM), until 1801 known as the Prime Minister of Great Britain, is the head of government of the United Kingdom. The Prime Minister directs both the executive and the legislature, and, together with the Prime Minister's Cabinet, (consisting of all the most senior ministers, most of whom are government department heads), is accountable to the Monarch, to Parliament, to the Prime Minister's political party and, ultimately, to the electorate for the policies and actions of the executive and the legislature.

By the 1830s 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 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-a-vis the Sovereign, Parliament and Cabinet.

William's and Anne's experiments with the political composition of the Cabinet illustrated the strengths of one party government and the weaknesses of coalition and minority governments. Nevertheless, it was not until the 1830s that the constitutional convention was established that the Sovereign must select the Prime Minister (and Cabinet) from the party whose views reflect those of the majority in Parliament. Since then, most ministries have reflected this one party rule.

When the general election of 2010 produced a hung parliament, the Conservative and Liberal Democrat parties agreed to form the Cameron¥Clegg coalition, the first coalition in seventy years. The previous coalition in the UK before 2010 was led by Conservative Prime Minister Winston Churchill during most of the Second World War, from May 1940 to May 1945. Clement Attlee, the leader of the Labour Party, served as deputy Prime Minister. After the general election of 2015, the nation returned to one party government after the Tories won an outright majority.

Following the Anglo-Irish Treaty of 6 December 1921, which was to be put into effect within one year, the enactment of the Irish Free State Constitution Act 1922 was concluded on 5 December 1922, creating the Irish Free State. Bonar Law, who had been in office as prime minister of Great Britain and Ireland for only six weeks, and who had just won the general election of November 1922, thus became the last prime minister whose responsibilities covered both Britain and the whole of Ireland. Most of a parliamentary session beginning on 20 November was devoted to the Act, and Bonar Law pushed through the creation of the Free State in the face of opposition from the "die hards".

Their conversion was reinforced after 1810. In that year, George III, who had suffered periodically from mental instability (possibly due to a blood disorder now known as porphyria), became permanently insane and spent the remaining 10 years of his life unable to discharge his duties. The Prince Regent was prevented from using the full powers of Kingship. The Regent became George IV in 1820, but during his 10-year reign was indolent and frivolous. Consequently, for 20 years the throne was virtually vacant and Tory Cabinets led by Tory Prime Ministers filled the void, governing virtually on their own.

Since 1722, most prime ministers have been members of the Commons; since 1902, all have had a seat there. Like other members, they are elected initially to represent only a constituency. Former Prime Minister Tony Blair, for example, represented Sedgefield in County Durham from 1983 to 2007. He became Prime Minister because in 1994 he was elected Labour Party leader and then led the party to victory in the 1997 general election, winning 418 seats compared to 165 for the Conservatives and gaining a majority in the House of Commons.

Grey set an example and a precedent for his successors. He was primus inter pares (first among equals), as Bagehot said in 1867 of the Prime Minister's status. Using his Whig victory as a mandate for reform, Grey was unrelenting in the pursuit of this goal, using every parliamentary device to achieve it. Although respectful toward the king, he made it clear that his constitutional duty was to acquiesce to the will of the people and Parliament.

Until 1911, Prime Ministers had to guide legislation through the Commons and the Lords and obtain majority approval in both houses for it to become law. This was not always easy, because political differences often separated the chambers. Representing the landed aristocracy, Lords Temporal were generally Tory (later Conservative) who wanted to maintain the status quo and resisted progressive measures such as extending the franchise. The party affiliation of members of the Commons was less predictable. During the 18th century its makeup varied because the Lords had considerable control over elections: sometimes Whigs dominated it, sometimes Tories. After the passage of the Great Reform Bill in 1832, the Commons gradually became more progressive, a tendency that increased with the passage of each subsequent expansion of the franchise.

Although the Commander-in-Chief of the British Armed Forces is legally the Sovereign, under constitutional practice the Prime Minister can declare war, and through the Secretary of State for Defence (a position which the PM may appoint, dismiss or even appoint themselves to), as chair of the Defence Council, exert power over the deployment and disposition of the UK's forces.