Far-left politics in the United Kingdom have existed since at least the 1840s, with the formation of various organisations following ideologies such as Marxism, revolutionary socialism, communism, anarchism and syndicalism.

Following the 1917 Russian Revolution and developments in international Marxism, new organisations advocated ideologies such as Marxism–Leninism, Left Communism and Trotskyism.

Following the Chinese Communist Revolution, further international developments from the 1960s led to the emergence of Maoist and later Hoxhaist groups. Political schisms within these tendencies created a large number of new political organisations, particularly from the 1960s to the 1990s.

Definition Ian Adams, in his Ideology and Politics in Britain Today, defines the British far-left as primarily those political organisations which are "committed to revolutionary Marxism.". He names specifically "orthodox communists, those influenced by the New Left Marxism of the 1960s, followers of Trotsky, of Mao Tse-tung, of Fidel Castro, and even Enver Hoxha.". He stated that although the British far-left is "highly complex", the main division is between the orthodox communists (i.e. Marxist-Leninists, sometimes called "Stalinists") and Trotskyists. John Callaghan likewise focuses his The Far Left in British Politics on the five largest Marxist organisations, namely the 'official' Communist Party and the four most influential Trotskyist groups. However, Evan Smith in Against the Grain: The British Far Left from 1956, uses the term 'far left' "to encompass all of the political currents to the left of the Labour Party," including "anarchist groups".

The scope of this article limits the discussion of far left politics to the period since 1801 i.e. the formation of the United Kingdom. However at least one historian has identified the existence of a 'far left' in England as early as the 1640s.

History

The early 19th century saw a series of "popular disturbances",Rudé, Eric The Crowd in History. A Study of Popular Disturbances in France and England, 1730–1848, New York: Wiley & Sons, 1964. New edition London: Serif, 2005, concerning mostly economic grievances and with little formal ideology or organisation (Luddites; Swing Riots; risings in Scotland and Wales), or which were related to reformist campaigns around legislation such as the Corn Laws, Reform Bills and Poor Law. There were also revolutionary conspiracies by small groups of radicals (Despard, Spa Fields, Cato Street) during and after the Napoleonic Wars. Chartism, however, was the first working class-led movement combining a national political organisation with what were arguably revolutionary aims.Royle, Edward Revolutionary Britannia? Reflections on the threat of revolution in Britain, 1789-1848 Manchester University Press, 2000, p170 However, even the politics of the minority of 'physical force' Chartists who plotted the abortive risings of 1839, 1840, 1842 and 1848 were largely Radical in nature and only a small number of Chartist leaders (O'Brien, Harney, Jones) moved towards Socialism. Far left politics such as revolutionary syndicalism were expressed in the trade union press from the early 1830s but were not the official policy of any organisation.

Background and early groups, 1840–1920

Far-left political groups have been active in the UK since the mid-19th century, beginning with the League of the Just from 1840, and the Marxist Communist League from 1847; groups with emigre origins. This emigre tradition continued throughout the century, for example German anarchist Johann Most established his Freiheit journal in London in 1879; editors included the Belgian Victor Dave. English socialist John Goodwyn Barmby had founded the 'Communist Propaganda Society' as early as 1841,Donald F. Busky (2002). Communism in History and Theory. Greenwood Publishing Group. p. 83. . but its Christian/Owenite foundations saw it evolve into the 'Communist Church' by 1843; his newspaper "Communist Chronicle" was later republished by fellow Chartist, Thomas Frost, who followed it with his own, short-lived "Communist Journal".

The earliest avowedly-Marxist national political party in Britain was the Social Democratic Federation (SDF), founded by Henry Hyndman in 1881, initially as the Democratic Federation, and renamed following the affiliation of the Labour Emancipation League (LEL, formed 1880) in 1884. Karl Marx and Friedrich Engels did not participate in the new "Marxist" organisation but the SDF counted among its members Marx's daughter Eleanor for a time, before she, her husband Edward Aveling, William Morris and the LEL broke away to found the libertarian Socialist League. Both parties were notable for not being willing to collaborate with "bourgeois" parties such as the Liberals on issues of reform, but differed on the question of participation in elections, which a majority of the Socialist League opposed. The SDF stood in elections from 1885 but with no success. The Socialist League suffered splits and gradual disintegration from 1888 - including the formation of the Bloomsbury Socialist Society and Hammersmith Socialist Society - and from 1889 until its dissolution in 1892 was effectively an anarchist organisation.Clayton, Joseph The Rise and Decline of Socialism in Great Britain 1884 to 1924, London: Faber & Gwyer, 1926, p38-9

Around the same time, reformist and ethical socialist groups emerged, such as the Fabian Society (1884) and Independent Labour Party (1893); the latter did not adhere strictly to the SDF's Marxist-derived scientific socialism and included a significant number of Christian socialists. An alliance between the three organisations did occur with the Labour Representation Committee in 1900, but this was not without tensions and led to fractures within the SDF.

The Social Democratic Federation also fractured over the issue of creeping reformism and also the Boer War of 1899–1902, with Hyndman himself eventually being less than enthusiastic about opposing it. The immediate issue which caused a significant portion of the hard left to split was the debate at the 5th Congress of the Second International in Paris, over the entry of Marxist Alexandre Millerand into the "bourgeois" French government of Pierre Waldeck-Rousseau. Those who opposed it, known as "Impossibilists", referred to supporters as "Opportunists" who were betraying revolutionary aims through class collaboration. Two notable groups broke with the SDF over this; the De Leonist-orientated Socialist Labour Party (SLP, formed 1903) of Neil Maclean (which also included James Connolly, later of Irish republican fame and was most prominent in Scotland) and the Socialist Party of Great Britain (formed 1904).

The period leading up to the First World War saw a renewal of industrial militancy outside of the mainstream Labour Movement's traditional commitment to parliamentary politics. The Industrialist League and Industrial Workers of Great Britain emerged in 1908-9 from the British Advocates of Industrial Unionism initially founded by the SLP. The Industrial Syndicalist Education League was formed the following year by dissident members of the SDF.

The SDF eventually morphed into a new Marxist party, the British Socialist Party, along with some members on the left of the ILP, with Hyndman leading. With the advent of the First World War conflict arose between "internationalist" and "national defence" factions, with Hyndman taking a nationalist stance. Vladimir Lenin, who had visited London six times from 1902 to 1911, was critical of this and supported the internationalists. Matters came to a head in 1916, when the defeated Hyndman left to found the National Socialist Party, while his internationalist opponents Alf watts, Zelda Kahan and Theodore Rothstein supported the Zimmerwald Conference. In Scotland, the BSP's John Maclean was involved in the Red Clydeside movement. From 1916 to 1920, the British Socialist Party would be the largest proto-communist party in Britain and, although affiliated to the Labour Party for the 1918 general election, was shortly afterwards the largest founding group of the Communist Party of Great Britain.

Marxist–Leninism in Britain, 1920–1947

The Communist Party of Great Britain (CPGB) was officially established in 1920 as the British Section of the Communist International (also known as the Third International) and adopted the theories of Leninism. The largest chunk of its members came from the British Socialist Party; the internationalist faction which had ousted Hyndman in 1916. Other groups involved were the Communist Unity Group (primarily from Glasgow), which had split from the De Leonist Socialist Labour Party, represented by the likes of Arthur MacManus, Tom Bell and William Paul and also the South Wales Socialist Society, which mainly consisted of Welsh coal-miners.

Unity was not unanimous however, as some other groups were founded outside of CPGB control; the Communist Party of South Wales and the West of England, the Communist Labour Party (based in Scotland, featuring John Maclean) and the Communist Party (British Section of the Third International) (associated with suffragette Sylvia Pankhurst). There was also the Communist League of Guy Aldred, which included not only Marxists, but also anarcho-communists. By January 1921, most of the aforementioned groups had joined the CPGB, with the exception of the Communist League, which became the Anti-Parliamentary Communist Federation (which came to oppose Leninism).

Studies of the period have revealed that in terms of participation, the Celtic fringe were over-represented, while the English were under-represented in the early days of British communism.. In particular, the communists gained working-class support among the Welsh in the Rhondda Valley and the Scots in West Fife (both being major mining areas at the time). Some of the Irish Catholic diaspora, especially in the big industrial cities of Britain, also played a role. As well as this "Celtic" tinge, prominent in the East End of London (Hackney, Whitechapel and Bethnal Green). were Jewish diaspora who had recently fled pogroms in the Russian Empire. John Maclean; the revolutionary best regarded by Lenin and the Russian Bolsheviks; played no role in the CPGB. He had claimed that the party's first MP, Cecil L'Estrange Malone and leading figure, Theodore Rothstein (who also wrote for the Manchester Guardian), were "police spies"; they in turn claimed that he was insane after his time of mistreatment in prison. By 1923, Maclean had died so the issue was at an end.

The far-left were thrust into the spotlight in the lead up to the 1924 general election, with the appearance of the "Zinoviev letter" in the Daily Mail. The sitting Labour government of Ramsay MacDonald had earlier in the year recognised the Soviet government as legitimate and in the letter, supposedly written by Grigory Zinoviev (head of the Comintern) to Arthur MacManus, it stated improving British-Soviet relations would have the effect of "revolutionising of the international and British proletariat not less than a successful rising in any of the working districts of England." The implication from the conservative press was that MacDonald and Labour were a Trojan horse for Bolshevism. For his part Zinoviev denied authorship, but it was widely believed in Britain at the time. It would not be until the late 1960s that researchers challenged its authenticity more fully and it is today regarded as a forgery. A number of activists, including Albert Inkpin spent time in prison under the Incitement to Mutiny Act 1797 in the mid-1920s.