The Socialist Labour Party was a socialist political party in the United Kingdom. It was established in 1903 as a splinter from the Social Democratic Federation (SDF) by James Connolly and SDF members impressed with the politics of the American socialist Daniel de Leon, who had formed a Socialist Labor Party in the USA.
The tendency first organised itself in 1902 around The Socialist newspaper, and when a leading member was expelled in 1903, most of the SDF's Scottish branches left to form the new party. Despite having substantive support in Scotland the majority of its membership was always in England.
The party was highly principled, and refused to work with reformists such as the SDF or the Independent Labour Party. Insisting on focusing on producing propaganda for the idea of an industrial union, they insisted members should avoid taking part in unemployment demonstrations as these were "sentimental" and built false hopes. The party argued for political action for propaganda purposes, but a syndicalist tendency the Advocates of Industrial Union split from the party in 1906, disclaiming all political work.
Headquartered in Scotland, and devoted to union-building, the SLP was well-placed to take a leading role in the Red Clydeside movement. They had a great deal of influence on the Clyde Workers Committee, but failed to win it to socialism. They abandoned their syndicalist strategy of creating a dual unions, and took up the position of working within existing unions to win them to their ideas.
From 1918, excited by the Bolshevik success in the Russian Revolution, the SLP opened talks with the British Socialist Party with the aim of forming a British Communist Party. The leadership could not agree with the BSP's plan to affiliate the new party to the Labour Party, and refused to join the Communist Party of Great Britain, but a faction formed the Communist Unity group and joined the CPGB.
The remainder of the SLP survived for many years, one splinter group (the Revolutionary Socialist Party) turning to Trotskyism, before finally disbanding in 1980.
