| Party |
Founded |
First represented |
Last represented |
Dissolved |
Maximum representation |
MPs |
Notes |
| Alba Party |
2021 |
2021 |
2024 |
N/A |
2 (2021) |
Kenny MacAskill; Neale Hanvey |
Split from the Scottish National Party |
| All-for-Ireland League |
1909 |
1909 |
1918 |
1918 |
8 (1910) |
|
|
| Alliance Party of Northern Ireland |
1970 |
1973 |
Present |
N/A |
1 (1973) |
Stephen Farry; Naomi Long; Stratton Mills; Sorcha Eastwood |
|
| Anti H-Block |
1981 |
1981 |
1982 |
1982 |
1 (1981) |
Bobby Sands; Owen Carron |
Merged into Sinn Féin |
| Anti-Waste League |
1921 |
1921 |
1922 |
1922 |
2 (1921) |
James Malcolm Monteith Erskine; Murray Sueter |
|
| Blaenau Gwent People's Voice |
2005 |
2010 |
2011 |
2011 |
1 (2010) |
Peter Law, Dai Davies |
|
| British Socialist Party |
1911 |
1920 |
1920 |
1920 |
1 (1920) |
Cecil L'Estrange Malone |
Merged into the Communist Party of Great Britain |
| Change UK |
2019 |
2019 |
2019 |
2019 |
11 (2019) |
List |
Split from the Labour and Conservative Parties in February 2019, dissolved December 2019 |
| Christian Pacifist (Fellowship of Reconciliation) |
1915 |
1923 |
1924 |
N/A |
1 (1923) |
George M. Ll. Davies |
|
| Coalition Labour |
1918 |
1918 |
1922 |
1922 |
|
|
| Colne Valley Labour Union |
1891 |
1907 |
1910 |
1918 |
1 (1907) |
Victor Grayson |
Won the 1907 Colne Valley by-election |
| Commonwealth Labour Party |
1942 |
1942 |
1947 |
1947 |
1 (1942) |
Harry Midgley |
|
| Common Wealth Party |
1942 |
1942 |
1946 |
1993 |
5 (1945) |
List |
|
| Communist Party of Great Britain |
1920 |
1920 |
1950 |
1991 |
2 (1945) |
Willie Gallacher; Cecil L'Estrange Malone; Walton Newbold; Phil Piratin; Shapurji Saklatvala |
|
| Conservative Party |
1835 |
1835 |
Present |
N/A |
473 (1931) |
List |
|
| Constitutionalists |
1923 |
1923 |
1925 |
1929 |
12 (1923) |
Winston Churchill, Hamar Greenwood, Algernon Moreing, Thomas Robinson, John Ward, Abraham England, Henry Hogbin, John Sturrock |
| Co-operative Party |
1917 |
1918 |
Present |
N/A |
38 (2017) |
List |
Affiliated with the Labour Party since 1927 |
| Democratic Labour |
1972 |
1972 |
1974 |
1979 |
1 (1972) |
Dick Taverne |
|
| Democratic Party |
1969 |
1969 |
1970 |
1971 |
1 (1969) |
Desmond Donnelly |
|
| Democratic Unionist Party |
1971 |
1971 |
Present |
N/A |
10 (2017) |
List |
Formed from the Protestant Unionist Party |
| Empire Free Trade Crusade |
1929 |
1930 |
1931 |
1930s |
1 (1930) |
Ernest Taylor |
Joint candidate with the United Empire Party |
| English National Party |
1960s |
1976 |
1976 |
1980 |
1 (1976) |
John Stonehouse |
|
| Federation of Labour |
1944 |
1945 |
1949 |
1949 |
1 (1945) |
Jack Beattie |
Merged into the Irish Labour Party |
| Green Party of England and Wales |
1973 |
1992 |
Present |
N/A |
4 (2024) |
Cynog Dafis; Caroline Lucas; Sian Berry; Carla Denyer; Ellie Chowns; Adrian Ramsay |
Dafis was a joint candidate with Plaid Cymru |
| Crofters Party |
1880s |
1885 |
1895 |
1890s |
4 (1885) |
Gavin Brown Clark; Charles Fraser-Mackintosh; Roderick MacDonald; Donald Horne Macfarlane |
|
| Independent Alliance (UK) |
2024 |
2024 |
Present |
N/A |
5 (2024) |
Jeremy Corbyn, Shockat Adam, Adnan Hussain, Iqbal Mohamed, Ayoub Khan |
Not a full-fledged party, but a Technical group |
| Independent Irish Party |
1852 |
1852 |
1858 |
1858 |
40 (1852) |
|
Split from the Liberal Party |
| Independent Kidderminster Hospital and Health Concern |
2000 |
2001 |
2010 |
N/A |
1 (2001) |
Richard Taylor |
|
| Independent Liberals |
1931 |
1931 |
1935 |
1935 |
5 (1931) |
David Lloyd George; Gwilym Lloyd George; Megan Lloyd George; Frank Owen; Goronwy Owen |
Not a separate party per se; its members were official Liberal Party candidates who rejected the National Government. |
| Independent Labour Party |
1893 |
1893 |
1947 |
1975 |
|
|
Affiliated with the Labour Party from 1900 until 1931 |
| Independent Parliamentary Group |
1920 |
1920 |
1921 |
1921 |
|
|
|
| Irish Confederate Party |
1847 |
1847 |
1848 |
1848 |
2 (1847) |
Thomas Chisholm Anstey; William Smith O'Brien |
|
| Irish Labour Party |
1912 |
1949 |
1955 |
N/A |
1 (1949) |
Jack Beattie |
|
| Labour Independent Group |
1949 |
1949 |
1950 |
1950 |
5 (1949) |
Lester Hutchinson; John Platts-Mills; Denis Nowell Pritt; Leslie Solley; Konni Zilliacus |
|
| Labour Party |
1906 |
1906 |
Present |
N/A |
418 (1997) |
List |
Formed from the Labour Representation Committee |
| Labour Independent Group |
1949 |
1949 |
1950 |
1950 |
5 (1949) |
Denis Pritt, Lester Hutchinson, John Platts-Mills, Leslie Solley, Konni Zilliacus |
Denis Pritt was expelled from the Labour Party in 1940 for supporting the Soviet Union in the Winter War, the rest were for supporting Soviet Foreign Policy |
| Labour Representation Committee |
1900 |
1900 |
1906 |
1906 |
29 (1906) |
List |
Became the Labour Party |
| Liberal Democrats |
1988 |
1988 |
Present |
N/A |
72 (2024) |
List |
Merger of the Liberal Party and the Social Democratic Party |
| Liberal Party |
1859 |
1859 |
1988 |
1988 |
397 (1906) |
List |
Merged into the Liberal Democrats |
| Liberal Unionist Party |
1886 |
1886 |
1912 |
1912 |
77 (1886) |
List |
Split from the Liberal Party; merged into the Conservative Party |
| Mebyon Kernow |
1951 |
1964 |
1970 |
N/A |
2 (1964) |
Peter Bessell, John Pardoe, David Mudd |
multi party membership |
| Militant tendency |
1964 |
1983 |
1991 |
1991 |
4 (1983) |
Eric Heffer, Dave Nellist, Terry Fields, Pat Wall |
| National Association of Discharged Sailors and Soldiers |
1916 |
1918 |
1921 |
1921 |
1 (1918) |
Robert Hewitt Barker |
Semi-official candidate, sponsored by local branch of organisation |
| National Democratic and Labour Party |
1918 |
1918 |
1922 |
1923 |
9 (1918) |
|
|
| National Party |
1917 |
1917 |
1921 |
1921 |
8 (1917) |
|
|
| Nationalist Party (Ireland) |
1870 |
1870 |
1955 |
1977 |
86 (1885) |
List |
|
| National Labour |
1931 |
1931 |
1945 |
1945 |
14 (1931) |
List |
|
| National Liberal Party |
1931 |
1931 |
1968 |
1968 |
55 (1950) |
List |
Affiliated with the Conservative Party from 1947 |
| National Socialist Party |
1916 |
1918 |
1919 |
1919 |
3 (1918) |
Dan Irving; Jack Jones; Will Thorne |
Affiliated with the Labour Party |
| New Party |
1930 |
1930 |
1931 |
1932 |
6 (1931) |
Oliver Baldwin; W. J. Brown; Robert Forgan; Cynthia Mosley; Oswald Mosley; John Strachey |
Baldwin and Brown held membership for a single day |
| Nordic League |
1935 |
1935 |
1939 |
1939 |
1 (1935) |
Archibald Maule Ramsay |
|
| Northern Ireland Labour Party |
1924 |
1943 |
1943 |
1987 |
1 (1943) |
Jack Beattie |
|
| Plaid Cymru |
1925 |
1966 |
Present |
N/A |
4 (1992) |
List |
|
| Protestant Unionist Party |
1966 |
1970 |
1971 |
1971 |
1 (1970) |
Ian Paisley |
Became the Democratic Unionist Party |
| Referendum Party |
1994 |
1997 |
1997 |
1997 |
1 (1997) |
George Gardiner |
|
| Republican Labour Party |
1964 |
1966 |
1970 |
1973 |
1 (1970) |
Gerry Fitt |
|
| Reclaim Party |
2020 |
2023 |
2023 |
N/A |
1 (2023) |
Andrew Bridgen |
| Reform League |
1865 |
1865 |
1869 |
1869 |
6 (1865) |
George Howell (trade unionist), Sir Wilfrid Lawson, 2nd Baronet, of Brayton, Peter Alfred Taylor, Samuel Morley (MP), Charles Bradlaugh, John Bright |
| Reform UK |
2018 |
2024 |
Present |
N/A |
8 (2026) |
List |
Founded as the Brexit Party |
| Respect Party |
2004 |
2005 |
2015 |
2016 |
1 (2005) |
George Galloway |
|
| Russellite Unionist |
1904 |
1904 |
1910 |
1910 |
3 (1904) |
Sir Thomas Russell, 1st Baronet, James Wood, Edward Mitchell, Robert Glendinning |
|
| Scotland United |
2023 |
2023 |
Present |
N/A |
3 (2023) |
Kenny MacAskill; Neale Hanvey; Angus MacNeil |
Political Grouping |
| Scottish Labour Party (1888) |
1888 |
1888 |
1892 |
1893 |
1 (1888) |
Robert Cunninghame-Graham |
Merged into the Independent Labour Party |
| Scottish Labour Party (1976) |
1976 |
1976 |
1979 |
1979 |
2 (1976) |
John Robertson; Jim Sillars |
Split from the Labour Party |
| Scottish National Party |
1934 |
1945 |
Present |
N/A |
56 (2015) |
List |
|
| Scottish Prohibition Party |
1901 |
1922 |
1931 |
1935 |
1 (1922) |
Edwin Scrymgeour |
|
| Sinn Féin |
1905 |
1917 |
Present |
N/A |
73 (1918) |
List |
Sinn Féin MPs do not take their seats |
| Social Democratic Party |
1981 |
1981 |
1988 |
1988 |
29 (1982) |
List |
Merged into the Liberal Democrats |
| Social Democratic Party (1988) |
1988 |
1988 |
1990 |
1990 |
29 (1982) |
Rosie Barnes, John Cartwright, David Owen |
Formed by Social Democratic Party members who did not join the Liberal Democrats |
| Social Democratic and Labour Party |
1970 |
1970 |
Present |
N/A |
4 (1992) |
List |
|
| Traditional Unionist Voice |
2007 |
2024 |
Present |
N/A |
1 (2024 |
Jim Allister |
|
| UK Unionist Party |
1995 |
1995 |
2001 |
2008 |
1 (1995) |
Robert McCartney |
|
| Ulster Popular Unionist Party |
1980 |
1980 |
1995 |
1995 |
1 (1980) |
James Kilfedder |
|
| Ulster Unionist Labour Association |
1918 |
1918 |
1922 |
N/A |
3 (1918) |
Thomas Henry Burn; Thompson Donald; Samuel McGuffin |
Linked with the Ulster Unionist Party |
| Ulster Unionist Party |
1905 |
1905 |
Present |
N/A |
20 (1918) |
List |
At times affiliated to the Conservative Party |
| United Empire Party |
1920s |
1930 |
1931 |
1930s |
1 (1930) |
Ernest Taylor |
Joint candidate with the Empire Free Trade Crusade |
| United Ulster Unionist Party |
1975 |
1975 |
1982 |
1982 |
1 (1975) |
John Dunlop |
Split from the Vanguard Unionist Progressive Party |
| UK Independence Party |
1993 |
2008 |
2017 |
N/A |
2 (2014) |
Douglas Carswell; Mark Reckless |
|
| Unity |
1960s |
1969 |
1974 |
1977 |
2 (1970) |
Bernadette Devlin; Frank McManus |
|
| Vanguard Unionist Progressive Party |
1973 |
1973 |
1978 |
1978 |
3 (1974) |
Robert Bradford; William Craig; John Dunlop |
Split from and later merged into the Ulster Unionist Party |
| Workers Party of Britain |
2019 |
2024 |
2024 |
N/A |
1 (2024) |
George Galloway |
| Your Party |
2025 |
2025 |
2025 |
N/A |
1 (2025) |
Zarah Sultana |
| Repeal Association |
1830 |
1832 |
1847 |
1848 |
42 (1832) |
|
Also Known as the Irish Repeal Party |
| Home Rule League |
1873 |
1874 |
1880 |
1882 |
59 (1874) |
|
Became the Irish Parliamentary Party |
| Liberal–Labour |
1870 |
1874 |
1918 |
1918 |
|
|
| Independent Conservative |
1911 |
1911 |
N/A |
N/A |
|
|
| Independent Nationalist |
1880 |
1880 |
1955 |
N/A |
N/A |
|
Not a Political Party but a Description for Irish Nationalist who are not affiliated with a Political Party same meaning as the Description used in the Northern Ireland Assembly today |
| Chartist |
1838 |
1847 |
1852 |
1857 |
1 (1847) |
|
|
| Birkenhead Social Justice |
2019 |
2019 |
2019 |
2019 |
1 (2019) |
|
|
| The Independents (UK) |
2019 |
2019 |
2019 |
2019 |
5 (2019) |
Gavin Shuker, John Woodcock, Luciana Berger, Angela Smith, Heidi Allen |
|
| Scottish Socialist Party (1932) |
1932 |
1932 |
1940 |
1940 |
2 (1932) |
Neil Maclean, Thomas Johnston |
|
| Ministerialist |
1768 |
1768 |
1774 |
1774 |
225 (1766) |
Lord North |
|
| Northite |
1774 |
1774 |
1784 |
1784 |
396 (1780) |
|
| Bedford Whigs |
1751 |
1751 |
1774 |
1783 |
23 (1751) |
|
|
| Rockingham Whigs |
1765 |
1768 |
1784 |
1784 |
254 (1780) |
William Dowdeswell, Henry Seymour Conway |
|
| Grenville Whigs |
1740 |
1765 |
1774 |
1774 |
41 (1768) |
George Grenville |
|
| Radicals |
1750 |
1768 |
1857 |
1859 |
15 (1852) |
|
|