25 Leaders of political parties in the United Kingdom

Natalie Louise Bennett, Baroness Bennett of Manor Castle is a British politician and journalist who served as Leader of the Green Party of England and Wales from 2012 to 2016. Bennett was given a peerage in Theresa May's 2019 resignation honours.

Mark Berry, better known as Bez, is an English percussionist, dancer, DJ and media personality. He is best known as a member of the rock bands Happy Mondays and Black Grape.

Harpal Brar is an Indian communist politician, writer and businessman, based in the United Kingdom. He is the founder and former chairman of the Communist Party of Great Britain (Marxist–Leninist), a role from which he stood down in 2018.

Gordon Michael Alexander Buchanan founded and has since either led or chaired the minor political party, Justice for Men and Boys (J4MB), in the United Kingdom. He is also a media commentator for the men's rights movement.

Rajani Palme Dutt, generally known as R. Palme Dutt, was a leading journalist and theoretician in the Communist Party of Great Britain.

John Gollan was a leader of the Communist Party of Great Britain (CPGB).

Nicholas John Griffin is a British politician who represented North West England as a Member of the European Parliament (MEP) from 2009 to 2014. He served as chairman and then president of the far-right British National Party (BNP) from 1999 to 2014, when he was expelled from the party.

Robert Griffiths is a Welsh communist activist and the current General Secretary of the Communist Party of Britain. He was elected by the party's Executive Committee in January 1998, in place of Mike Hicks.

Michael Joseph Hicks was a British politician, executive member of printers’ union SOGAT, and general secretary of the Communist Party of Britain.

Alan "Howling Laud" Hope is a British politician and the Leader of the Official Monster Raving Loony Party (OMRLP). On the death of the party's founder Screaming Lord Sutch in 1999, Hope and his pet cat, Catmando, were jointly elected as leaders of the OMRLP. Since June 2002 Hope has been the party's sole leader following Catmando's death in a road accident.

Katharine Jane Hudson is a British left-wing political activist and academic who is the General Secretary of the Campaign for Nuclear Disarmament (CND) and Media Officer of Left Unity. She served as Chair of CND from 2003 to 2010. She has been an officer of the Stop the War Coalition since 2002.

Albert Samuel Inkpin was a British communist and the first General Secretary of the Communist Party of Great Britain (CPGB). He served several terms in prison for political offences. In 1929 he was replaced as head of the CPGB and made head of the party's Friends of Soviet Russia organisation, a position he retained until his death.

Laurence "Loz" Kaye is a British musician, composer, activist and politician. Kaye was Leader of Pirate Party UK from 26 September 2010 to 9 May 2015.

Caroline Patricia Lucas is a British politician who has twice led the Green Party of England and Wales and has been the Member of Parliament (MP) for Brighton Pavilion since the 2010 general election. She was re-elected in the 2015, 2017 and 2019 general elections, increasing her majority each time.

Gordon McLennan was General Secretary of the Communist Party of Great Britain (CPGB) between 1975-1990.

Harry Pollitt was a British communist who served as the General Secretary of the Communist Party of Great Britain (CPGB) from 1929 to September 1939 and again from 1941 until his death in 1960. Pollitt spent most of his life advocating communism. Ideologically a Marx-Leninist, Pollitt was an adherent particularly of Joseph Stalin even after Stalin's death and disavowal by Khrushchev. Pollitt's acts included opposition to the Allied intervention in the Russian Civil War and Polish–Soviet War, support for the Spanish Republicans during the Spanish Civil War, both support and opposition to the war against Nazi Germany, defence of the communist coup in Czechoslovakia, and criticism of British colonialism.

The Liberal Party is a British political party that was founded in 1989 as a continuation of the original Liberal Party by former members who opposed its merger with the Social Democratic Party (SDP) to form the Liberal Democrats. The party holds eight local council seats.

John Rees-Evans is a British politician, currently the leader of the Five Star Direct Democracy Party. He was associated with the UK Independence Party (UKIP) from 2015 to 2017, contesting their leadership in November 2016, coming third with 18.1% of the vote, and again in 2017, coming fourth.

Helena Sanders née Charles was a Cornish humanitarian, cultural activist, politician and poet. Sanders was the founder of the political party, Mebyon Kernow, in 1951. She was also well known for her feline welfare efforts in Venice.

Arthur Scargill is a British trade unionist who was President of the National Union of Mineworkers (NUM) from 1982 to 2002. He is best known for leading the 1984–1985 miners' strike, a major event in the history of the British labour movement.

David Edward Sutch, also known as 3rd Earl of Harrow, or Screaming Lord Sutch, was an English musician and serial parliamentary candidate. He was the founder of the Official Monster Raving Loony Party and served as its leader from 1983 to 1999, during which time he stood in numerous parliamentary elections. He holds the record for contesting the most Parliamentary elections, standing in 39 elections from 1963 to 1997. As a singer he variously worked with Keith Moon, Jeff Beck, Jimmy Page, Ritchie Blackmore, Charlie Watts, John Bonham and Nicky Hopkins, and is known for his 1963 novelty hit "Jack the Ripper".

Robin C. W. Tilbrook is an English solicitor and political leader who chairs the English Democrats, a political party he founded. It advocates a devolved English Parliament, having previously advocated English independence from the United Kingdom.

John Hutchyns Tyndall was a British fascist political activist. A leading member of various small neo-Nazi groups during the late 1950s and 1960s, he was chairman of the National Front (NF) from 1972 to 1974 and again from 1975 to 1980, and then chairman of the British National Party (BNP) from 1982 to 1999. He unsuccessfully stood for election to the House of Commons and European Parliament on several occasions.

Anne Marie Dorothy Waters is a far-right politician and activist in the United Kingdom. She is the founder and leader of the anti-Islam party For Britain. She is also the director of Sharia Watch UK, an organisation launched in April 2014. In January 2016, Waters launched Pegida UK in conjunction with activist Tommy Robinson and far-right politician Paul Weston.