List of prime ministers of the United Kingdom

Top left: Robert Walpole is considered the first prime minister of Great Britain.
Top right: Winston Churchill was prime minister during much of World War II.
Bottom left: Margaret Thatcher was the first female prime minister.
Bottom right: Keir Starmer is the incumbent prime minister.

The prime minister of the United Kingdom is the principal minister of the crown of His Majesty's Government, and the head of the British Cabinet.

There is no specific date for when the office of prime minister first appeared, as the role was not created but rather evolved over time through a merger of duties.^[1] The term was regularly, if informally, used by Robert Walpole by the 1730s.^[2] It was used in the House of Commons as early as 1805,^[3] and it was certainly in parliamentary use by the 1880s,^[4] although did not become the official title until 1905, when Arthur Balfour was prime minister.

Historians generally consider Robert Walpole, who led the government of the Kingdom of Great Britain for over twenty years from 1721,^[5] to be the first prime minister. Walpole is also the longest-serving British prime minister by this definition.^[6] The first prime minister of the United Kingdom of Great Britain and Ireland was William Pitt the Younger at its creation on 1 January 1801.^[7] The first to use the title in an official act was Benjamin Disraeli who signed the 1878 Treaty of Berlin as "Prime Minister of Her Britannic Majesty".^[8]

In 1905, the post of prime minister was officially given recognition in the order of precedence,^[9] with the incumbent Henry Campbell-Bannerman the first officially referred to as "prime minister". The first prime minister of the current United Kingdom of Great Britain and Northern Ireland upon its effective creation in 1922 (when 26 Irish counties seceded and created the Irish Free State) was Bonar Law,^[10] although the country was not renamed officially until 1927, when Stanley Baldwin was the serving prime minister.^[11]

The incumbent prime minister is Keir Starmer, who assumed the office on 5 July 2024.

^ Hennessy 2001, pp. 39–40.
^ Stephen Taylor ODNB.^{[full citation needed]}
^ Castlereagh 1805.
^ Eardley-Wilmot 1885; Macfarlane 1885.
^ Clarke 1999, p. 266; Hennessy 2001, pp. 39–40.
^ BBC News 1998.
^ Burt 1874, p. 106; Castlereagh 1805.
^ Bogdanor 1997.
^ Marriott 1923, p. 83.
^ Law 1922.
^ Royal and Parliamentary Titles Act 1927.

[FOOTNOTEHennessy200139–40-1] Hennessy 2001, pp. 39–40.

[2] Stephen Taylor ODNB.^{[full citation needed]}

[FOOTNOTECastlereagh1805-3] Castlereagh 1805.

[FOOTNOTEEardley-Wilmot1885Macfarlane1885-4] Eardley-Wilmot 1885; Macfarlane 1885.

[FOOTNOTEClarke1999266Hennessy200139–40-5] Clarke 1999, p. 266; Hennessy 2001, pp. 39–40.

[FOOTNOTEBBC_News1998-6] BBC News 1998.

[FOOTNOTEBurt1874106Castlereagh1805-7] Burt 1874, p. 106; Castlereagh 1805.

[FOOTNOTEBogdanor1997-8] Bogdanor 1997.

[FOOTNOTEMarriott192383-9] Marriott 1923, p. 83.

[FOOTNOTELaw1922-10] Law 1922.

[FOOTNOTERoyal_and_Parliamentary_Titles_Act1927-11] Royal and Parliamentary Titles Act 1927.

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