British left

Progressives and social democrats believe that equality can be accommodated into existing capitalist structures, but they differ in their criticism of capitalism and on the extent of reform and the welfare state.

[1][2][3] Leftism in the United Kingdom is thought to stretch back to the aftermath of the English Civil War in the 17th century, represented by groups such as the 'True Levellers' or Diggers.

[49] The other three political parties on the left and with representation in parliament are the centre-left Social Democratic and Labour Party (SDLP) of Northern Ireland; the centre-left Plaid Cymru (who are only active in Wales) and Sinn Féin, also from Northern Ireland.

[55] The party was subsequently criticised by some, including Blair himself, as straying leftwards from the centre ground of British politics,[56] and that Miliband was a more traditional left-wing politician.

[57] Others disputed this view, and put Labour's loss at the 2015 United Kingdom general election down to the party being too right-wing.

[70] While not winning, Labour made significant gains in terms of vote share and modest improvements in terms of seats, enough to deny a Conservative majority and led to a hung parliament, at the 2017 United Kingdom general election,[71][72] which was taken as a vindication by some of the left turn.

[75][76][77] In 2015, the membership of the Green Party of England and Wales quadrupled, and its support in national opinion polls sextupled.

[78] Several factors contributed, including the collapse of the Lib Dem vote, the influence of social media and greater awareness among younger people about the rise of other left-wing parties in Europe such as: Podemos in Spain and Syriza in Greece, as well as a rise in anti-austerity movements across the UK and Europe.

[80] The party also received a significant spike in membership during January 2015 following David Cameron's demand that the Greens be included in the leaders' debates for the 2015 general election.

[84] In the 2021 United Kingdom local elections, the party made a net gain of 91 council seats, taking its national total to a record 444.

[93] In May 2017, TUSC confirmed that it would stand no candidates at the forthcoming general election,[93] and give full support to Labour.

[95] In September 2020, TUSC became active once again as its steering committee agreed it would stand candidates in the 2021 local elections.

[100] In 2017, the CPB announced that it would field no candidates at that year's general election, and give support to Labour instead.