# List of political parties in the United Kingdom by representation

This is a list of political parties in the United Kingdom, by their historic representation in elected bodies.

## British House of Commons

| 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 | | | 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 | N/A | N/A | 5 (2024) | Lee Anderson; Nigel Farage; Rupert Lowe; Richard Tice; James McMurdock | 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 | 2017 | 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 | N/A | N/A | 1 (2024) | George Galloway |
| 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) | |
| Rockingham Whigs | 1765 | 1768 | 1784 | 1784 | 254 (1780) | William Dowdeswell, Henry Seymour Conway | |
| Grenville Whigs | 1740 | 1765 | 1774 | 1774 | 41 (1768) | George Grenville | |
| Bedford Whigs | 1751 | 1751 | 1774 | 1783 | 23 (1751) | | |
| Radicals | 1750 | 1768 | 1857 | 1859 | 15 (1852) | | |

## London Assembly

| Party | Founded | First represented | Last represented | Dissolved | Maximum representation | AMs | Notes |
| Brexit Alliance | 2018 | 2018 | 2021 | 2021 | 2 (2018) | Peter Whittle, David Kurten | |
| British National Party | 1982 | 2008 | 2010 | N/A | 1 (2008) | Richard Barnbrook | Was expelled from party in first term |
| Conservative and Unionist Party | 1835 | 2000 | N/A | N/A | 11 (2008) | | |
| London Green Party | 1990 | 2000 | N/A | N/A | 3 (2000) | | |
| Heritage Party | 2020 | 2020 | 2021 | N/A | 1 (2020) | David Kurten | |
| Labour and Co-Operative Party | 1909 | 2000 | N/A | N/A | 12 (2012) | | |
| Liberal Democrats | 1988 | 2000 | N/A | N/A | 5 (2004) | | |
| One London | 2005 | 2005 | 2008 | 2008 | 2 (2005) | Damian Hockney, Peter Hulme-Cross | |
| UK Independence Party | 1993 | 2004 | 2020 | N/A | 2 (2004) | Damian Hockney, Peter Hulme-Cross, Peter Whittle, David Kurten | |
| Veritas | 2005 | 2005 | 2005 | 2015 | 2 (2005) | Damian Hockney, Peter Hulme-Cross | Briefly before Forming One London |

## British House of Lords

| Party | Founded | First represented | Last represented | Dissolved | Maximum representation | Members | Notes |
| British People's Party | 1939 | 1939 | 1953 | 1954 | 3 (1943) | Gerard Wallop, 9th Earl of Portsmouth, Hastings Russell, 12th Duke of Bedford, Ronald Nall-Cain, 2nd Baron Brocket | |
| British Fascists | 1923 | 1923 | 1934 | 1934 | 1 (1923) | Leopold Ernest Stratford George Canning, 4th Baron Garvagh |
| British Union of Fascists | 1932 | 1940 | 1932 | 1940 | 7 (1936) | Patrick Boyle, David Freeman-Mitford, Josslyn Hay, Edward Russell, Hastings Russell, Harold Harmsworth, Edward Frederick Langley Russell | |
| Communist Party of Great Britain | 1920 | 1962 | 1991 | 1991 | 1 (1962) | Wogan Philipps | |
| Conservative Party | 1835 | 1835 | Present | N/A | | | |
| Green Party of England and Wales | 1973 | 1980s | Present | N/A | 1 (1999) | George MacLeod; Timothy Beaumont, Baron Beaumont of Whitley; Jenny Jones, Baroness Jones of Moulsecoomb | |
| Labour Party | 1906 | 1924 | Present | N/A | | | |
| Liberal Democrats | 1988 | 1988 | Present | N/A | | | Merger of the Liberal Party and the Social Democratic Party |
| Liberal Party | 1859 | 1859 | 1988 | 1988 | | | Merged into the Liberal Democrats |
| National Party | 1917 | 1917 | 1921 | 1921 | 3 (1917) | Oliver Russell, 2nd Baron Ampthill, Sir Richard Cooper, 2nd Baronet, Henry Page Croft, 1st Baron Croft |
| Nordic League | 1935 | 1935 | 1939 | 1939 | 2 (1935) | Arthur Wellesley, 5th Duke of Wellington, Ronald Nall-Cain, 2nd Baron Brocket |
| Social Democratic Party | 1981 | 1981 | 1988 | 1988 | | | Merged into the Liberal Democrats |
| Social Democratic Party (1988) | 1988 | 1988 | 1990 | 1990 | 17 (1988) | | Continuation of the Social Democratic Party |
| United Kingdom Independence Party | 1993 | 1990s | 2019 | N/A | 2 (2007) | Richard Norton, 8th Baron Grantley; Malcolm Pearson, Baron Pearson of Rannoch; David Verney, 21st Baron Willoughby de Broke | |
| Universal League for the Material Elevation of the Industrious Classes | 1863 | 1863 | 1865 | 1865 | 1 (1863) | John Townshend, 5th Marquess Townshend | |

## Northern Ireland Assembly

| Party | Founded | First represented | Last represented | Dissolved | Maximum representation | MLAs | Notes |
| Alliance Party of Northern Ireland | 1973 | 1998 | Present | N/A | 17 (2022) | John Alderdice; Kellie Armstrong; Eileen Bell; John Blair; Paula Bradshaw; Patrick Brown; Seamus Close; Judith Cochrane; Stewart Dickson; Danny Donnelly; Sorcha Eastwood; Connie Egan; Stephen Farry; David Ford; Máire Hendron; David Honeyford; Anna Lo; Naomi Long; Trevor Lunn; Chris Lyttle; Kieran McCarthy; Peter McReynolds; Nick Mathison; Nuala McAllister; Andrew Muir; Seán Neeson; Kate Nicholl; Patricia O'Lynn; Eóin Tennyson | |
| Anti-Partition League | 1945 | 1953 | 1958 | 1958 | 2 (1953) | Eddie McAteer, Malachy Conlon |
| Commonwealth Labour Party | 1942 | 1945 | 1947 | 1947 | 1 (1942) | Only MP and Founder Defected to the Ulster Unionist Party |
| Democratic Unionist Party | 1971 | 1998 | Present | N/A | 38 (2011) | | |
| Fianna Uladh | 1953 | 1953 | 1954 | 1954 | 1 (1953) | Liam Kelly (Irish republican) | |
| Green Party in Northern Ireland | 1983 | 2007 | 2022 | N/A | 2 (2016) | Steven Agnew; Clare Bailey; Brian Wilson; Rachel Woods | |
| Labour coalition | 1996 | 1998 | 1998 | 1998 | 2 (1996) | Malachi Curran, Hugh Casey | |
| Irish Labour Party | 1912 | 1951 | 1963 | N/A | 1 (1951) | |
| Nationalist Party (Northern Ireland) | 1918 | 1921 | 1973 | 1977 | 11 (1929) | | |
| NI21 | 2013 | 2013 | 2016 | 2016 | 2 (2013) | Basil McCrea, John McCallister | Split from the Ulster Unionist Party |
| Northern Ireland Labour Party | 1924 | 1925 | 1975 | 1987 | 4 (1958) | | |
| Northern Ireland Women's Coalition | 1996 | 1996 | 2003 | 2006 | 2 (1996) | Monica McWilliams, Pearl Sagar | |
| Northern Ireland Unionist Party | 1999 | 1999 | 2003 | 2008 | 4 (1999) | Norman Boyd; Roger Hutchinson; Patrick Roche; Cedric Wilson | Split from the UK Unionist Party |
| Northern Ireland Women's Coalition | 1996 | 1998 | 2003 | 2006 | 2 (1998) | Monica McWilliams; Jane Morrice | |
| People Before Profit Alliance | 2005 | 2016 | Present | N/A | 2 (2016) | Gerry Carroll; Eamonn McCann | |
| Progressive Unionist Party | 1979 | 1998 | 2010 | N/A | 2 (1998) | Billy Hutchinson; Dawn Purvis; David Ervine | |
| Sinn Féin | 1905 | 1921 | Present | N/A | 29 (2011) | | |
| Social Democratic and Labour Party | 1970 | 1998 | Present | N/A | 24 (1998) | | |
| Socialist Republican Party | 1944 | 1944 | 1950 | 1950 | 1 (1944) | Harry Diamond |
| Traditional Unionist Voice | 2007 | 2011 | Present | N/A | 1 (2011) | Jim Allister | |
| UK Independence Party | 1993 | 2012 | 2016 | N/A | 1 (2012) | David McNarry |
| UK Unionist Party | 1995 | 1998 | 2007 | 2008 | 5 (1998) | Norman Boyd; Roger Hutchinson; Robert McCartney; Patrick Roche; Cedric Wilson | |
| Ulster Democratic Party | 1981 | 1996 | 1998 | 2001 | 2 (1996) | John White, Gary McMichael |
| Ulster Popular Unionist Party | 1980 | 1982 | 1986 | 1993 | 1 (1992) | James Kilfedder | |
| United Unionist Assembly Party | 1998 | 1998 | 2003 | N/A | 3 (1998) | Fraser Agnew; Boyd Douglas; Denis Watson | |
| Ulster Unionist Party | 1905 | 1921 | Present | N/A | 28 (1998) | | |
| Unbought Tenants' Association | 1913? | 1925 | 1929 | ? | 1 (1925) | George Henderson |
| Fianna Fáil | 1933 | 2011 | 2011 | N/A | 1 (2007) | Gerry McHugh | Believed that "Fianna Fáil was the right party to bring about change in Northern Ireland". |

## Scottish Parliament

| Party | Founded | First represented | Last represented | Dissolved | Maximum representation | MSPs | Notes |
| Alba Party | 2021 | 2023 | N/A | N/A | 1 (2023) | Ash Regan | |
| Save Stobhill Hospital | 2001 | 2003 | 2007 | N/A | 1 (2003) | Jean Turner | |
| MSP for Falkirk West | 1999 | 1999 | 2007 | N/A | 1 (1999) | Dennis Canavan | |
| Scottish Conservative and Unionist Party | 1965 | 1999 | Present | N/A | 31 (2016) | | |
| Scottish Green Party | 1990 | 1999 | Present | N/A | 8 (2021) | | |
| Scottish Labour Party | 1909 | 1999 | Present | N/A | 56 (1999) | | |
| Scottish Liberal Democrats | 1988 | 1999 | Present | N/A | 17 (1999) | | |
| Scottish National Party | 1934 | 1999 | Present | N/A | 69 (2011) | | |
| Scottish Senior Citizens Unity Party | 2003 | 2003 | 2007 | N/A | 1 (2003) | John Swinburne | |
| Scottish Socialist Party | 1998 | 1999 | 2007 | N/A | 6 (2003) | | |
| Solidarity | 2006 | 2006 | 2007 | N/A | 2 (2006) | Rosemary Byrne; Tommy Sheridan | Split from the Scottish Socialist Party |
| RISE – Scotland's Left Alliance | 2015 | 2015 | 2016 | N/A | 1 (2016) | Jean Urquhart | Split from the Scottish National Party |
| Reform Scotland | 2021 | 2021 | 2021 | N/A | 1 (2021) | Michelle Ballantyne | Split from the Scottish Conservative and Unionist Party |
| Scottish Peoples' Alliance | 2003 | 2003 | 2003 | 2010 | 2 (2003) | Lyndsay McIntosh, Keith Harding | Briefly defected after being ranked down in the list, lost their seats. |

## Welsh Parliament (formerly: National Assembly of Wales)

| Party | Founded | First represented | Last represented | Dissolved | Maximum representation | AMs/MSs | Notes |
| John Marek Independent Party/Forward Wales | 2003 | 2003 | 2007 | 2003 (John Marek Independent Party)/2010 (Forward Wales) | 1 (2003) | John Marek | |
| Plaid Cymru | 1925 | 1999 | Present | N/A | 17 (1999) | | |
| United Kingdom Independence Party | 1993 | 2016 | 2021 | 2021 | 7 (2016) | | |
| Wales Labour Party | 1947 | 1999 | Present | N/A | 30 (2003) | | |
| Welsh Conservative Party | 1921 | 1999 | Present | N/A | 13 (2009) | | |
| Welsh Liberal Democrats | 1988 | 1999 | Present | N/A | 6 (1999) | | |
| Propel | 2020 | 2021 | 2021 | N/A | 1 (2020) | Neil McEvoy | Spilt from the Plaid Cyrmu; the party gained four councillors a month after the party's formation |
| Blaenau Gwent People's Voice | 2005 | 2010 | 2011 | 1 (2010) | Peter Law, Dai Davies | |
| Abolish the Welsh Assembly Party | 2015 | 2020 | 2021 | N/A | 2 (2020) | Gareth Bennett; Mark Reckless | Prior to Bennett's joining the party, the party's got its first councillor, who defected from the Welsh Conservative Party, a month earlier. Later that year, Reckless, the former leader, of the Brexit Party of Wales, joined the party, |
| Independent Alliance for Reform | 2020 | 2020 | 2021 | 2021 | 3 (2020) | Caroline Jones, David Rowlands, Mandy Jones |
| Brexit Party | 2018 | 2018 | 2020 | N/A | 4 (2020) | Caroline Jones, David Rowlands, Mandy Jones, Mark Reckless |

## European Parliament

| Party | Founded | First represented | Last represented | Dissolved | Maximum representation | MEPs | Notes |
| Alliance Party of Northern Ireland | 1970 | 2019 | 2020 | N/A | 1 (2019) | Naomi Long | |
| British Democratic Party | 2013 | 2013 | 2014 | N/A | 1 (2013) | Andrew Brons | |
| British National Party | 1982 | 2009 | 2014 | N/A | 2 (2009) | Andrew Brons; Nick Griffin | |
| Brexit Party | 2019 | 2019 | 2020 | N/A | 23 (2019) | List | |
| Change UK – The Independent Group | 2019 | 2019 | 2019 | N/A | 1 (2019) | List | |
| Conservative Party | 1835 | 1979 | 2020 | N/A | 60 (1979) | | |
| Democratic Unionist Party | 1971 | 1979 | 2020 | N/A | 1 (1979) | Jim Allister; Diane Dodds; Ian Paisley | |
| Gibraltar Socialist Labour Party | 1978 | 1999 | 2009 | N/A | 1 (1999) | Glyn Ford | Joint List |
| Green Party of England and Wales | 1973 | 1999 | 2020 | N/A | 3 (2014) | Jean Lambert; Caroline Lucas; Keith Taylor; Molly Scott Cato | |
| Independent Labour Network | 1999 | 1999 | 1999 | 2003 | 1 (1999) | Ken Coates | Split from the Labour Party |
| Labour Party | 1906 | 1979 | 2020 | N/A | 62 (1994) | | |
| Liberal Democrats | 1988 | 1994 | 2020 | N/A | 12 (2004) | | |
| Libertarian Party | 2007 | 2018 | 2019 | N/A | 1 (2019) | Bill Etheridge | The briefly got first representative in October 2018, but soon their representative later joined the Brexit Party in February 2019. |
| Plaid Cymru | 1925 | 1999 | 2020 | N/A | 2 (1999) | Jillian Evans; Eurig Wyn | |
| Pro-Euro Conservative Party | 1999 | 1999 | 1999 | 2001 | 2 (1999) | Brendan Donnelly; John Stevens | Split from the Conservative Party |
| Scottish National Party | 1934 | 1979 | 2020 | N/A | 2 (1994) | Winifred Ewing; Ian Hudghton; Allan Macartney; Neil MacCormick; Alyn Smith | |
| Scottish Socialist Party | 1998 | 1998 | 1999 | N/A | 1 (1998) | Hugh Kerr | |
| Sinn Féin | 1905 | 2004 | 2020 | N/A | 1 (2004) | Bairbre de Brún; Martina Anderson | Also had an MEP elected in the Republic of Ireland |
| Social Democratic and Labour Party | 1970 | 1979 | 2004 | N/A | 1 (1979) | John Hume | |
| Social Democratic Party | 1981 | 1984 | 1984 | 1988 | 1 (1984) | Michael Gallagher | |
| Social Democratic Party (1990-present) | 1990 | 2018 | 2019 | N/A | 1 (2018) | Patrick O'Flynn | This is the second continuation and current incarnation of the original Social Democratic Party |
| Thurrock Independents | 2018 | 2018 | 2019 | N/A | 1 (2018) | Tim Aker | |
| Traditional Unionist Voice | 2007 | 2007 | 2009 | N/A | 1 (2007) | Jim Allister | |
| United Kingdom Independence Party | 1993 | 1999 | 2019 | N/A | 24 (2014) | | |
| Ulster Unionist Party | 1905 | 1979 | 2019 | N/A | 1 (1979) | Jim Nicholson; John Taylor | |
| Veritas | 2005 | 2005 | 2005 | 2015 | 1 (2005) | Robert Kilroy-Silk | Split from the United Kingdom Independence Party; merged into the English Democrats |