Prime Minister

The first person to be called Prime Minister was Sir Robert Walpole, who served as First Lord of the Treasury from 1721 to 1742. Until 1905, there was no official office of Prime Minister. Rather, it was an unofficial title pertaining to the head of the ministry, who was usually the First Lord of the Treasury.
Name 	Entered office 	Left office 	Party 	Notes
Robert Walpole later Sir Robert Walpole 	4 April 1721 	11 February 1742	Whig 	First Lord of the Treasury and Chancellor of the Exchequer. Regarded as the first Prime Minister in the modern sense.
The Earl of Wilmington 	16 February 1742	2 July 1743 	Whig 	First Lord of the Treasury. the government was led de facto by Lord Carteret, the Secretary of State for the Northern Department.
Henry Pelham 	27 August 1743 	6 March 1754 	Whig 	First Lord of the Treasury and Chancellor of the Exchequer. Until the end of 1744, the government was led de facto by Lord Carteret, the Secretary of State for the Northern Department.
The Duke of Newcastle-upon-Tyne 	16 March 1754 	16 November 1756	Whig 	First Lord of the Treasury
The Duke of Devonshire 	16 November 1756	25 June 1757 	Whig 	First Lord of the Treasury. The government was largely run by William Pitt the Elder, the Secretary of State for the Southern Department, until his resignation in April 1757.
The Duke of Newcastle-upon-Tyne 	2 July 1757 	26 May 1762 	Whig 	First Lord of the Treasury. William Pitt the Elder, as Secretary of State for the Southern Department, was virtually co-prime minister until his resignation late in 1761. He was succeeded in this role by the Earl of Bute, the Secretary of State for the Northern Department.
The Earl of Bute 	26 May 1762 	16 April 1763 	Tory 	First Lord of the Treasury
George Grenville 	16 April 1763 	13 July 1765 	Whig 	First Lord of the Treasury and Chancellor of the Exchequer
The Marquess of Rockingham 	13 July 1765 	30 July 1766 	Whig 	First Lord of the Treasury
The Earl of Chatham 	30 July 1766 	14 October 1768 	Whig 	Lord Privy Seal. Was in ill health for most of his time as Prime Minister. The Duke of Grafton, as First Lord of the Treasury, acted as prime minister for most of this time.
The Duke of Grafton 	14 October 1768 	28 January 1770 	Whig 	First Lord of the Treasury from July 1766.
Lord North 	28 January 1770 	22 March 1782 	Tory 	First Lord of the Treasury and Chancellor of the Exchequer (from 1767)
The Marquess of Rockingham 	27 March 1782 	1 July 1782 	Whig 	First Lord of the Treasury.
The Earl of Shelburne 	4 July 1782 	2 April 1783 	Whig 	First Lord of the Treasury
The Duke of Portland 	2 April 1783 	19 December 1783	Whig 	First Lord of the Treasury.
William Pitt 	19 December 1783	14 March 1801 	Tory 	First Lord of the Treasury and Chancellor of the Exchequer.
Henry Addington 	17 March 1801 	10 May 1804 	Tory 	First Lord of the Treasury and Chancellor of the Exchequer.
William Pitt 	10 May 1804 	23 January 1806 	Tory 	First Lord of the Treasury and Chancellor of the Exchequer
The Lord Grenville 	11 February 1806	31 March 1807 	Whig 	First Lord of the Treasury.
The Duke of Portland 	31 March 1807 	4 October 1809 	Whig 	First Lord of the Treasury. He was old and ill, leaving the Cabinet to their own devices, although no one figure was dominant.
Spencer Perceval 	4 October 1809 	11 May 1812 	Tory 	First Lord of the Treasury, Chancellor of the Exchequer, and Chancellor of the Duchy of Lancaster.
The Earl of Liverpool 	9 June 1812 	10 April 1827 	Tory 	First Lord of the Treasury
George Canning 	10 April 1827 	8 August 1827 	Tory 	First Lord of the Treasury and Chancellor of the Exchequer
The Viscount Goderich 	31 August 1827 	22 January 1828 	Tory 	First Lord of the Treasury
The Duke of Wellington 	22 January 1828 	22 November 1830	Tory 	First Lord of the Treasury
The Earl Grey 	November 1830 	16 July 1834 	Whig 	First Lord of the Treasury
The Viscount Melbourne 	16 July 1834 	17 November 1834	Whig 	First Lord of the Treasury
The Duke of Wellington(caretaker) 	17 November 1834	9 December 1834 	Tory 	First Lord of the Treasury and Secretary of State for Foreign Affairs
Sir Robert Peel, Bt. 	9 December 1834 	18 April 1835 	Tory 	First Lord of the Treasury and Chancellor of the Exchequer
The Viscount Melbourne 	18 April 1835 	30 August 1841 	Whig 	First Lord of the Treasury
Sir Robert Peel, Bt. 	30 August 1841 	30 June 1846 	Conservative 	First Lord of the Treasury
Lord John Russell 	30 June 1846 	23 February 1852	Whig 	First Lord of the Treasury
The Earl of Derby 	23 February 1852	19 December 1852	Conservative 	First Lord of the Treasury
The Earl of Aberdeen 	19 December 1852	6 February 1855 	Peelite 	First Lord of the Treasury
The Viscount Palmerston 	6 February 1855 	20 February 1858	Liberal 	First Lord of the Treasury
The Earl of Derby 	20 February 1858	12 June 1859 	Conservative 	First Lord of the Treasury
The Viscount Palmerston 	12 June 1859 	29 October 1865 	Liberal 	First Lord of the Treasury
The Earl Russell 	29 October 1865 	28 June 1866 	Liberal 	First Lord of the Treasury
The Earl of Derby 	28 June 1866 	27 February 1868	Conservative 	First Lord of the Treasury
Benjamin Disraeli 	27 February 1868	3 December 1868 	Conservative 	First Lord of the Treasury
William Gladstone 	3 December 1868 	20 February 1874	Liberal 	First Lord of the Treasury and (from 1873-1874) Chancellor of the Exchequer
Benjamin Disraeli later The Earl of Beaconsfield	20 February 1874	23 April 1880 	Conservative 	First Lord of the Treasury
William Gladstone 	23 April 1880 	23 June 1885 	Liberal 	First Lord of the Treasury and (1880-1882) Chancellor of the Exchequer
The Marquess of Salisbury 	23 June 1885 	1 February 1886 	Conservative 	Secretary of State for Foreign Affairs
William Gladstone 	1 February 1886 	25 July 1886 	Liberal 	First Lord of the Treasury
The Marquess of Salisbury 	3 August 1886 	15 August 1892 	Conservative 	First Lord of the Treasury (1886-1887) and then Secretary of State for Foreign Affairs (1887-1892)
William Gladstone 	15 August 1892 	5 March 1894 	Liberal 	First Lord of the Treasury
The Earl of Rosebery 	5 March 1894 	25 June 1895 	Liberal 	First Lord of the Treasury
The Marquess of Salisbury 	25 June 1895 	11 July 1902 	Conservative 	Secretary of State for Foreign Affairs (1895-1900), and then Lord Privy Seal (1900-1902)
Arthur Balfour 	11 July 1902 	5 December 1905 	Conservative 	First Lord of the Treasury; the first to hold the title of Prime Minister officially. Henceforth, all Prime Ministers are also First Lord of the Treasury.
Sir Henry Campbell-Bannerman 	5 December 1905 	7 April 1908 	Liberal 	 
Herbert Henry Asquith 	7 April 1908 	7 December 1916 	Liberal 	 
David Lloyd George 	7 December 1916 	23 October 1922 	Liberal 	 
Andrew Bonar Law 	23 October 1922 	22 May 1923 	Conservative 	 
Stanley Baldwin 	22 May 1923 	22 January 1924 	Conservative 	 
Ramsay MacDonald 	22 January 1924 	4 November 1924 	Labour 	also Secretary of State for Foreign Affairs
Stanley Baldwin 	4 November 1924 	5 June 1929 	Conservative 	 
Ramsay MacDonald 	5 June 1929 	7 June 1935 	Labour (1929-1931), then National Labour (1931-1935)	 
Stanley Baldwin 	7 June 1935 	28 May 1937 	Conservative 	 
Neville Chamberlain 	28 May 1937 	10 May 1940 	Conservative 	 
Winston Churchill 	10 May 1940 	27 July 1945 	Conservative 	also Minister of Defence
Clement Attlee 	27 July 1945 	26 October 1951 	Labour 	also Minister of Defence (1945-1946)
Winston Churchill later Sir Winston Churchill 	26 October 1951 	6 April 1955 	Conservative 	also Minister of Defence (1951-1952)
Sir Anthony Eden 	6 April 1955 	10 January 1957 	Conservative 	 
Harold Macmillan 	10 January 1957 	19 October 1963 	Conservative 	 
Sir Alec Douglas-Home 	19 October 1963 	16 October 1964 	Conservative 	 
Harold Wilson 	16 October 1964 	19 June 1970 	Labour 	 
Edward Heath 	19 June 1970 	4 March 1974 	Conservative 	 
Harold Wilson 	4 March 1974 	5 April 1976 	Labour 	 
James Callaghan 	5 April 1976 	4 May 1979 	Labour 	 
Margaret Thatcher 	4 May 1979 	28 November 1990	Conservative 	 
John Major 	28 November 1990	2 May 1997 	Conservative 	 
Tony Blair 	2 May 1997 	27 June 2007 	Labour 	 
Gordon Brown 	27 June 2007 	11 May 2010 	Labour 	 
David Cameron 	11 May 2010 	13 July 2016 	Conservative 	 
Theresa May 	13 July 2016 	incumbent 	Conservative