• Top left: Robert Walpole was the first prime minister and longest serving of Great Britain.
• Top right: Winston Churchill was the prime minister during much of World War II.
• Bottom left: Margaret Thatcher was the first female prime minister.
• Bottom right: Boris Johnson is the current prime minister.

The prime minister of the United Kingdom is the head of the Government of the United Kingdom, and chair 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 a period of time through a merger of duties.^[1] However, the term was regularly, if informally, used of 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] In 1905 the post of prime minister was officially given recognition in the order of precedence.^[5] Modern historians generally consider Sir Robert Walpole, who led the government of Great Britain for over twenty years from 1721,^[6] as the first prime minister. Walpole is also the longest-serving British prime minister by this definition.^[7] However, Sir Henry Campbell-Bannerman was the first and Margaret Thatcher the longest-serving prime minister officially referred to as such in the order of precedence.^[8] The first to use the title in an official act was Benjamin Disraeli, who signed the Treaty of Berlin as "Prime Minister of her Britannic Majesty" in 1878.^[9]

Strictly speaking, the first prime minister of the United Kingdom of Great Britain and Ireland was William Pitt the Younger.^[10] The first prime minister of the current United Kingdom, i.e. the United Kingdom of Great Britain and Northern Ireland, was Bonar Law,^[11] although the country was not renamed officially until 1927, when Stanley Baldwin was the serving prime minister.^[12]

Due to the gradual evolution of the post of prime minister, the title is applied to early prime ministers only retrospectively;^[13] this has sometimes given rise to academic dispute. Lord Bath and Lord Waldegrave are sometimes listed as prime ministers.^[14] Bath was invited to form a ministry by George II when Henry Pelham resigned in 1746,^[15] as was Waldegrave in 1757 after the dismissal of William Pitt the Elder,^[16] who dominated the affairs of government during the Seven Years' War. Neither was able to command sufficient parliamentary support to form a government; Bath stepped down after two days,^[14] and Waldegrave after three.^[16] Modern academic consensus does not consider either man to have held office as prime minister,^[17] and they are therefore listed separately.

Before 1721

Prior to the Georgian era, the Treasury of England was led by the Lord High Treasurer.^[18] By the late Tudor period, the Lord High Treasurer was regarded as one of the Great Officers of State,^[18] and was often (though not always) the dominant figure in government: Edward Seymour, 1st Duke of Somerset (Lord High Treasurer, 1547–1549),^[19] served as Lord Protector to his prepubescent nephew Edward VI;^[19] William Cecil, 1st Baron Burghley (Lord High Treasurer, 1572–1598),^[20] was the dominant minister to Elizabeth I;^[20] Burghley's son Robert Cecil, 1st Earl of Salisbury, succeeded his father as chief minister to Elizabeth I (1598–1603) and was eventually appointed by James I as Lord High Treasurer (1608–1612).^[21]

By the late Stuart period, the Treasury was often run not by a single individual (i.e., the Lord High Treasurer) but by a commission of Lords of the Treasury,^[22] led by the First Lord of the Treasury. The last Lords High Treasurer, Lord Godolphin (1702–1710) and Lord Oxford (1711–1714),^[23] ran the government of Queen Anne.^[24]

After the succession of George I in 1714, the arrangement of a commission of Lords of the Treasury (as opposed to a single Lord High Treasurer) became permanent.^[25] For the next three years, the government was headed by Lord Townshend, who was appointed Secretary of State for the Northern Department.^[26] Subsequently, Lord Stanhope and Lord Sunderland ran the government jointly,^[27] with Stanhope managing foreign affairs and Sunderland domestic.^[27] Stanhope died in February 1721 and Sunderland resigned two months later;^[27] Townshend and Robert Walpole were then invited to form the next government.^[28] From that point, the holder of the office of First Lord also usually (albeit unofficially) held the status of prime minister. It was not until the Edwardian era that the title prime minister was constitutionally recognised.^[13] The prime minister still holds the office of First Lord by constitutional convention,^[29] the only exceptions being Lord Chatham (1766–1768) and Lord Salisbury (1885–1886, 1887–1892, 1895–1902).^[30]

From 1721

Whig (16)   Tory (10)   Conservative (19)   Liberal (7)   Labour (6)   National Labour (1)   Peelite (1)									Monarch	Ref.
Portrait		Title Prime Minister Office (Birth–Death)	Term of office & mandate[a] Duration in years and days			Ministerial offices held as prime minister	Party	Government
		Sir Robert Walpole (1676–1745)	3 April 1721	11 February 1742	1722	Chancellor of the Exchequer First Lord of the Treasury Leader of the House of Commons	Whig	Walpole–Townshend	George I 1714–1727	[31]
					1727				George II 1727–1760
					1734			Walpole
					1741
			20 years and 315 days
		Spencer Compton 1st Earl of Wilmington (1673–1743)	16 February 1742	2 July 1743	—	First Lord of the Treasury	Whig	Carteret		[32]
			1 year and 137 days[†]
​		Henry Pelham (1694–1754)	27 August 1743	6 March 1754	—	Chancellor of the Exchequer First Lord of the Treasury Leader of the House of Commons	Whig			[33]
								Broad Bottom I
					1747			Broad Bottom II
			10 years and 192 days[†]
		Thomas Pelham-Holles 1st Duke of Newcastle (1693–1768)	16 March 1754	11 November 1756	1754	First Lord of the Treasury Leader of the House of Lords	Whig	Newcastle I		[34]
			2 years and 241 days
		William Cavendish 4th Duke of Devonshire (1720–1764)	16 November 1756	29 June 1757	—	First Lord of the Treasury Leader of the House of Lords Lord Treasurer of Ireland	Whig	Pitt–Devonshire		[35]
								1757 Caretaker
			226 days
​		Thomas Pelham-Holles 1st Duke of Newcastle (1693–1768)	29 June 1757	26 May 1762	1761	First Lord of the Treasury Leader of the House of Lords	Whig	Pitt–Newcastle		[36]
								Bute–Newcastle (Tory–Whig)	George III 1760–1820
			4 years and 332 days
		John Stuart 3rd Earl of Bute (1713–1792)	26 May 1762	8 April 1763	—	First Lord of the Treasury Leader of the House of Lords	Tory	Bute		[37]
			318 days
		George Grenville (1712–1770)	16 April 1763	10 July 1765	—	Chancellor of the Exchequer First Lord of the Treasury Leader of the House of Commons	Whig (Grenvillite)	Grenville (mainly Whig)		[38]
			2 years and 86 days
		Charles Watson-Wentworth 2nd Marquess of Rockingham (1730–1782)	13 July 1765	30 July 1766	—	First Lord of the Treasury Leader of the House of Lords	Whig (Rockinghamite)	Rockingham I		[39]
			1 year and 18 days
		William Pitt the Elder 1st Earl of Chatham (1708–1778)	30 July 1766	14 October 1768	1768	Lord Privy Seal	Whig (Chathamite)	Chatham		[40]
			2 years and 77 days
		Augustus FitzRoy 3rd Duke of Grafton (1735–1811)	14 October 1768	28 January 1770	—	First Lord of the Treasury Leader of the House of Lords	Whig (Chathamite)	Grafton		[41]
			1 year and 107 days
		Frederick North Lord North (1732–1792)	28 January 1770	27 March 1782	1774	Chancellor of the Exchequer First Lord of the Treasury Leader of the House of Commons	Tory (Northite)	North		[42]
					1780
			12 years and 59 days
		Charles Watson-Wentworth 2nd Marquess of Rockingham (1730–1782)	27 March 1782	1 July 1782	—	First Lord of the Treasury	Whig (Rockinghamite)	Rockingham II		[39]
			97 days[†]
		William Petty 2nd Earl of Shelburne (1737–1805)	4 July 1782	26 March 1783	—	First Lord of the Treasury Leader of the House of Lords	Whig (Chathamite)	Shelburne		[43]
			266 days
		William Cavendish-Bentinck 3rd Duke of Portland (1738–1809)	2 April 1783	18 December 1783	—	First Lord of the Treasury Leader of the House of Lords	Whig	Fox–North		[44]
			261 days
		William Pitt the Younger (1759–1806)	19 December 1783	14 March 1801	1784	Chancellor of the Exchequer First Lord of the Treasury Leader of the House of Commons	Tory (Pittite)	Pitt I		[45]
					1790
					1796
			17 years and 86 days
		Henry Addington (1757–1844)	17 March 1801	10 May 1804	1801	Chancellor of the Exchequer First Lord of the Treasury Leader of the House of Commons	Tory (Addingtonian)	Addington		[46]
					1802
			3 years and 55 days
		William Pitt the Younger (1759–1806)	10 May 1804	23 January 1806	—	Chancellor of the Exchequer First Lord of the Treasury Leader of the House of Commons	Tory (Pittite)	Pitt II		[47]
			1 year and 259 days[†]
		William Grenville 1st Baron Grenville (1759–1834)	11 February 1806	25 March 1807	1806	First Lord of the Treasury Leader of the House of Lords	Whig	All the Talents (Whig–Tory)		[48]
			1 year and 43 days
		William Cavendish-Bentinck 3rd Duke of Portland (1738–1809)	31 March 1807	4 October 1809	1807	First Lord of the Treasury	Tory (Pittite)	Portland II		[49]
			2 years and 188 days
		Spencer Perceval (1762–1812)	4 October 1809	11 May 1812	—	Chancellor of the Duchy of Lancaster Chancellor of the Exchequer Commissioner of the Treasury for Ireland (1810–1812) First Lord of the Treasury Leader of the House of Commons	Tory (Pittite)	Perceval		[50]
			2 years and 221 days[†]
		Robert Jenkinson 2nd Earl of Liverpool (1770–1828)	8 June 1812	9 April 1827	1812	First Lord of the Treasury Leader of the House of Lords	Tory (Pittite)	Liverpool		[51]
					1818				George IV 1820–1830
					1820
					1826
			14 years and 306 days
		George Canning (1770–1827)	12 April 1827	8 August 1827	—	Chancellor of the Exchequer First Lord of the Treasury Leader of the House of Commons	Tory (Canningite)	Canning (Canningite–Whig)		[52]
			119 days[†]
		Frederick John Robinson 1st Viscount Goderich (1782–1859)	31 August 1827	8 January 1828	—	First Lord of the Treasury Leader of the House of Lords	Tory (Canningite)	Goderich		[53]
			131 days
		Arthur Wellesley 1st Duke of Wellington (1769–1852)	22 January 1828	16 November 1830	1830	First Lord of the Treasury Leader of the House of Lords	Tory	Wellington–Peel		[54]
			2 years and 299 days						William IV 1830–1837
		Charles Grey 2nd Earl Grey (1764–1845)	22 November 1830	9 July 1834	1831	First Lord of the Treasury Leader of the House of Lords	Whig	Grey		[55]
					1832
			3 years and 230 days
		William Lamb 2nd Viscount Melbourne (1779–1848)	16 July 1834	14 November 1834	—	First Lord of the Treasury Leader of the House of Lords	Whig	Melbourne I		[56]
			122 days
		Arthur Wellesley 1st Duke of Wellington (1769–1852)	17 November 1834	9 December 1834	—	First Lord of the Treasury Leader of the House of Lords Sec. of State for Foreign Affairs Sec. of State for the Home Dept Sec. of State for War & Colonies	Tory	Wellington Caretaker		[57]
			23 days
		Sir Robert Peel (1788–1850)	10 December 1834	8 April 1835	—	Chancellor of the Exchequer First Lord of the Treasury Leader of the House of Commons	Conservative	Peel I		[58]
			120 days
		William Lamb 2nd Viscount Melbourne (1779–1848)	18 April 1835	30 August 1841	1835	First Lord of the Treasury Leader of the House of Lords	Whig	Melbourne II		[59]
					1837				Victoria 1837–1901
			6 years and 135 days
		Sir Robert Peel (1788–1850)	30 August 1841	29 June 1846	1841	First Lord of the Treasury Leader of the House of Commons	Conservative	Peel II		[58]
			4 years and 304 days
		Lord John Russell (1792–1878)	30 June 1846	21 February 1852	1847	First Lord of the Treasury Leader of the House of Commons	Whig	Russell I		[60]
			5 years and 237 days
		Edward Smith-Stanley 14th Earl of Derby (1799–1869)	23 February 1852	17 December 1852	1852	First Lord of the Treasury Leader of the House of Lords	Conservative	Who? Who?		[61]
			299 days
		George Hamilton-Gordon 4th Earl of Aberdeen (1784–1860)	19 December 1852	30 January 1855	—	First Lord of the Treasury Leader of the House of Lords	Peelite	Aberdeen (Peelite–Whig–et al.)		[62]
			2 years and 43 days
		Henry John Temple 3rd Viscount Palmerston (1784–1865)	6 February 1855	19 February 1858	1857	First Lord of the Treasury Leader of the House of Commons	Whig	Palmerston I		[63]
			3 years and 14 days
		Edward Smith-Stanley 14th Earl of Derby (1799–1869)	20 February 1858	11 June 1859	—	First Lord of the Treasury Leader of the House of Lords	Conservative	Derby–Disraeli II		[64]
			1 year and 112 days
		Henry John Temple 3rd Viscount Palmerston (1784–1865)	12 June 1859	18 October 1865	1859	First Lord of the Treasury Leader of the House of Commons	Liberal	Palmerston II		[65]
					1865
			6 years and 129 days[†]
		John Russell 1st Earl Russell (1792–1878)	29 October 1865	26 June 1866	—	First Lord of the Treasury Leader of the House of Lords	Liberal	Russell II		[60]
			241 days
		Edward Smith-Stanley 14th Earl of Derby (1799–1869)	28 June 1866	25 February 1868	—	First Lord of the Treasury Leader of the House of Lords	Conservative	Derby–Disraeli III		[66]
			1 year and 243 days
		Benjamin Disraeli (1804–1881)	See also § Main articles:1			First Lord of the Treasury Leader of the House of Commons	Conservative			[67]
			27 February 1868	1 December 1868	—
			279 days
		William Ewart Gladstone (1809–1898)	See also § Main articles:2			Chancellor of the Exchequer (1873–1874) First Lord of the Treasury Leader of the House of Commons	Liberal	Gladstone I		[68]
			3 December 1868	17 February 1874	1868
			5 years and 77 days
		Benjamin Disraeli 1st Earl of Beaconsfield (1804–1881)	See also § Main articles:1			First Lord of the Treasury Leader of the House of Commons (1874–1876) Leader of the House of Lords (1876–1880) Lord Privy Seal (1876–1878)	Conservative	Disraeli II		[69]
			20 February 1874	21 April 1880	1874
			6 years and 62 days
		William Ewart Gladstone (1809–1898)	See also § Main articles:2			Chancellor of the Exchequer (1880–1882) First Lord of the Treasury Leader of the House of Commons	Liberal	Gladstone II		[70]
			23 April 1880	9 June 1885	1880
			5 years and 48 days
		Robert Gascoyne-Cecil 3rd Marquess of Salisbury (1830–1903)	23 June 1885	28 January 1886	—	Leader of the House of Lords Sec. of State for Foreign Affairs	Conservative	Salisbury I		[71]
			220 days
		William Ewart Gladstone (1809–1898)	See also § Main articles:2			First Lord of the Treasury Leader of the House of Commons Lord Privy Seal	Liberal	Gladstone III		[70]
			1 February 1886	20 July 1886	1885
			170 days
		Robert Gascoyne-Cecil 3rd Marquess of Salisbury (1830–1903)	25 July 1886	11 August 1892	1886	First Lord of the Treasury (1886–1887) Leader of the House of Lords Sec. of State for Foreign Affairs (1887–1892)	Conservative	Salisbury II		[72]
			6 years and 18 days
		William Ewart Gladstone (1809–1898)	See also § Main articles:2			First Lord of the Treasury Leader of the House of Commons Lord Privy Seal	Liberal	Gladstone IV		[70]
			15 August 1892	2 March 1894	1892
			1 year and 200 days
		Archibald Primrose 5th Earl of Rosebery (1847–1929)	5 March 1894	22 June 1895	—	First Lord of the Treasury Leader of the House of Lords Lord President of the Council	Liberal	Rosebery		[73]
			1 year and 110 days
		Robert Gascoyne-Cecil 3rd Marquess of Salisbury (1830–1903)	25 June 1895	11 July 1902	1895	Leader of the House of Lords Lord Privy Seal (1900–1902) Sec. of State for Foreign Affairs (1895–1900)	Conservative	Salisbury III (Con.–Lib.U.)		[74]
					1900			Salisbury IV	Edward VII 1901–1910
			7 years and 17 days
		Arthur Balfour (1848–1930)	12 July 1902	4 December 1905	—	First Lord of the Treasury Leader of the House of Commons Lord Privy Seal (1902–1903)	Conservative	Balfour		[75]
			3 years and 146 days
		Sir Henry Campbell-Bannerman (1836–1908)	5 December 1905	3 April 1908	1906	First Lord of the Treasury Leader of the House of Commons	Liberal	Campbell-Bannerman		[76]
			2 years and 121 days
		H. H. Asquith (1852–1928)	8 April 1908	5 December 1916	—	First Lord of the Treasury Leader of the House of Commons Sec. of State for War (1914)	Liberal	Asquith I		[77]
					Jan.1910			Asquith II	George V 1910–1936
					Dec.1910			Asquith III
					—			Asquith Coalition (Lib.–Con.–et al.)
			8 years and 243 days
		David Lloyd George (1863–1945)	6 December 1916	19 October 1922	—	First Lord of the Treasury	Liberal	Lloyd George War		[78]
					1918			Lloyd George II (Lib.–Con.)
			5 years and 318 days
		Andrew Bonar Law (1858–1923)	23 October 1922	20 May 1923	1922	First Lord of the Treasury Leader of the House of Commons	Conservative (Scot.U.)	Law		[79]
			210 days
		Stanley Baldwin (1867–1947)	22 May 1923	22 January 1924	—	Chancellor of the Exchequer (1923) First Lord of the Treasury Leader of the House of Commons	Conservative	Baldwin I		[80]
			246 days
		Ramsay MacDonald (1866–1937)	22 January 1924	4 November 1924	1923	First Lord of the Treasury Leader of the House of Commons Sec. of State for Foreign Affairs	Labour	MacDonald I		[81]
			288 days
		Stanley Baldwin (1867–1947)	4 November 1924	4 June 1929	1924	First Lord of the Treasury Leader of the House of Commons	Conservative	Baldwin II		[82]
			4 years and 213 days
		Ramsay MacDonald (1866–1937)	5 June 1929	7 June 1935	1929	First Lord of the Treasury Leader of the House of Commons	Labour	MacDonald II		[83]
					—		National Labour	National I (N.Lab.–Con.–et al.)
					1931			National II
			6 years and 3 days
​		Stanley Baldwin (1867–1947)	7 June 1935	28 May 1937	1935	First Lord of the Treasury Leader of the House of Commons	Conservative	National III		[84]
									Edward VIII 1936
			1 year and 356 days						George VI 1936–1952
		Neville Chamberlain (1869–1940)	28 May 1937	10 May 1940	—	First Lord of the Treasury Leader of the House of Commons	Conservative	National IV		[85]
								Chamberlain War
			2 years and 349 days
		Winston Churchill (1874–1965)	10 May 1940	26 July 1945	—	First Lord of the Treasury Leader of the House of Commons (1940–1942) Minister of Defence	Conservative	Churchill War		[86]
			5 years and 78 days					Churchill Caretaker (Con.–L.Nat.)
		Clement Attlee (1883–1967)	26 July 1945	26 October 1951	1945	First Lord of the Treasury Minister of Defence (1945–1946)	Labour	Attlee I		[87]
					1950			Attlee II
			6 years and 93 days
		Sir Winston Churchill (1874–1965)	26 October 1951	5 April 1955	1951	First Lord of the Treasury Minister of Defence (1951–1952)	Conservative	Churchill III		[88]
			3 years and 162 days						Elizabeth II 1952–present
		Sir Anthony Eden (1897–1977)	6 April 1955	9 January 1957	1955	First Lord of the Treasury	Conservative	Eden		[89]
			1 year and 279 days
		Harold Macmillan MP for Bromley (1894–1986)	10 January 1957	18 October 1963	—	First Lord of the Treasury	Conservative	Macmillan I		[90]
					1959			Macmillan II
			6 years and 282 days
		Sir Alec Douglas-Home[b] MP for Kinross and Western Perthshire (1903–1995)	19 October 1963	16 October 1964	—	First Lord of the Treasury	Conservative (Scot.U.)	Douglas-Home		[91]
			364 days
		Harold Wilson MP for Huyton (1916–1995)	16 October 1964	19 June 1970	1964	First Lord of the Treasury Minister for the Civil Service (1968–1970)	Labour	Wilson I		[92]
					1966			Wilson II
			5 years and 247 days
		Edward Heath MP for Bexley (1916–2005)	19 June 1970	4 March 1974	1970	First Lord of the Treasury Minister for the Civil Service	Conservative	Heath		[93]
			3 years and 259 days
		Harold Wilson MP for Huyton (1916–1995)	4 March 1974	5 April 1976	Feb.1974	First Lord of the Treasury Minister for the Civil Service	Labour	Wilson III		[92]
					Oct.1974			Wilson IV
			2 years and 33 days
		James Callaghan MP for Cardiff South and Penarth (1912–2005)	5 April 1976	4 May 1979	—	First Lord of the Treasury Minister for the Civil Service	Labour	Callaghan		[94]
			3 years and 30 days
		Margaret Thatcher MP for Finchley (1925–2013)	See also § Main articles:3			First Lord of the Treasury Minister for the Civil Service	Conservative	Thatcher I		[95]
			4 May 1979	28 November 1990	1979
					1983			Thatcher II
					1987			Thatcher III
			11 years and 209 days
		John Major (born 1943) MP for Huntingdon	28 November 1990	2 May 1997	—	First Lord of the Treasury Minister for the Civil Service	Conservative	Major I		[96]
					1992			Major II
			6 years and 156 days
		Tony Blair (born 1953) MP for Sedgefield	See also § Main articles:4			First Lord of the Treasury Minister for the Civil Service	Labour	Blair I		[97]
			2 May 1997	27 June 2007	1997
					2001			Blair II
					2005			Blair III
			10 years and 57 days
		Gordon Brown (born 1951) MP for Kirkcaldy and Cowdenbeath	See also § Main articles:5			First Lord of the Treasury Minister for the Civil Service	Labour	Brown		[98]
			27 June 2007	11 May 2010	—
			2 years and 319 days
		David Cameron (born 1966) MP for Witney	See also § Main articles:6			First Lord of the Treasury Minister for the Civil Service	Conservative	Cameron–Clegg (Con.–Lib.Dems.)		[99]
			11 May 2010	13 July 2016	2010
					2015			Cameron II
			6 years and 64 days
		Theresa May (born 1956) MP for Maidenhead	See also § Main articles:7			First Lord of the Treasury Minister for the Civil Service	Conservative	May I		[100]
			13 July 2016	24 July 2019	—
					2017			May II
			3 years and 12 days
		Boris Johnson (born 1964) MP for Uxbridge and South Ruislip	See also § Main articles:8			First Lord of the Treasury Minister for the Civil Service Minister for the Union	Conservative	Johnson I
			24 July 2019	Incumbent	—
					2019			Johnson II
			1 year and 262 days
Title Prime Minister Office (Birth–Death)			Term of office & mandate			Ministerial offices	Party	Government	Monarch	Ref.

Disputed

Whig (2)									Monarch
Title Prime Minister Office (Birth–Death)			Term of office & mandate[a] Duration in years and days			Ministerial offices held as prime minister	Party	Government
		William Pulteney 1st Earl of Bath (1684–1764)	10 February 1746	12 February 1746	–	First Lord of the Treasury	Whig	Short Lived	George II (1727–1760)
			3 days
		James Waldegrave 2nd Earl Waldegrave (1715–1763)	8 June 1756	12 June 1756	–			Waldegrave
			5 days

Living former officeholders

As of April 2021, there are five living former British prime ministers. The most recent to die was Margaret Thatcher (1979–1990), on 8 April 2013.