[1] The SDF battled through defections of its right and left wings to other organisations in the first decade of the twentieth century before uniting with other radical groups in the Marxist British Socialist Party from 1911 until 1920.

The British Marxist movement effectively began in 1880 when a businessman named Henry M. Hyndman read Karl Marx's Communist Manifesto in French translation while crossing to America.

[7] The programme of the SDF was strongly progressive, calling for (amongst other measures) a 48-hour workweek, the abolition of child labour, compulsory and free and secular education, equality for women, and the nationalisation of the means of production, distribution, and exchange by a democratic state.

[8] The party attracted to its banner a number of Britain's leading radicals, including William Morris, Edward Aveling and his partner Eleanor Marx, Karl's youngest daughter.

One key to his personal authority lay in his purse, which paid the bulk of its administrative expenses,[9] and its weekly newspaper, Justice, lost money despite a healthy circulation of about 3,500.

Hyndman was additionally accused of stirring up strife between members of the Council and fabricating a provincial branch from thin air so as to ready himself to wield undeserved voting authority at a future convention of the organisation.

Hyndman gathered his factional supporters for his defence, while his opponents, who included William Morris, Belfort Bax, Eleanor Marx, and Edward Aveling, mustered their own forces.

After protracted debate, on 27 December a motion of censure on Hyndman was adopted, after which the majority of the Council, freshly victorious, promptly resigned from the SDF.

[15] Friedrich Engels was jubilant about the split, declaring to Eduard Bernstein: "I have the satisfaction of having seen through the whole racket from the outset, correctly sized up all the people concerned, and foretold what the end would be.

"[16] Unfortunately for Engels' best laid plans, it was the Socialist League that wound up "shipwrecked" by the split, while the SDF emerged from the factional strife with Hyndman and his followers in tighter control than before.

[17] The defection of assorted and sundry anti-parliamentary members from the Social Democratic Federation, including a fair number of anarchists, to form the Socialist League in 1885 left the SDF a relatively more homogeneous unit than its new offshoot.

[18] While Hyndman and the SDF used scare tactics about some impending national catastrophe that would prove the catalyst for socialist revolution in the mid-1880s, his eyes remained on the parliamentary prize.

This body of police and military forces used horses, batons, and rifle butts against an estimated 20,000 demonstrators out of the square, injuring hundreds and killing two in the process.

Some 40,000 demonstrators turned out at Hyde Park to voice their outrage over the "Bloody Sunday" killings, while an additional large crowd gathered in Trafalgar Square.

On 27 February 1900 Hyndman and the SDF met with the ILP, the Fabian Society and trade union leaders at the Memorial Hall in Farringdon Street, London.

Despite the formal unification of forces, many members of the party were uncomfortable with the Marxism of the SDF and Hyndman had very little influence over the development of this political group, eventually leaving the alliance in 1907.

"[33] Charges of reformism and chauvinism were made by left wing members, who began publishing their oppositional criticism in the official organ of the Socialist Labor Party of America.

At the March 1902 annual conference of the SDF, held in Blackburn, the battle between the insurgent left wing and Hyndman's leadership group came to a head.

Before the proceedings began, George Yates was informed that he was to be expelled from the party for purportedly obstructing left unity, failing to sell Justice, and writing an editorial for The Socialist in which he declared that there was a "distinct tendency" of the SDF to alter their former revolutionary attitude in favour of "opportunist tactics of the worst kind.

The departing left wing particularly faulted the SDF's perceived failure to concentrate on work to radicalise the nation's trade unions, which was envisioned as being the key to the revolutionary transformation of society.