[1] Following the Allied victory in World War I and the success of the Bolsheviks in the October Revolution, a growing number of British anarchists became increasingly attracted to Marxist theory and began to synthesize a form of "anarcho-Marxism".
This process culminated in an attempt to unite the anarcho-communists with the anti-parliamentary socialists under a single formation, an initiative that was taken up by dissident London branch of the SLP,[2] which in February 1919 proposed the convocation of a unity conference to bring together the nascent British communist movement.
A South Wales branch was also established by coal miners in Treherbert, led by the Welsh trade unionist William Mainwaring, who registered his disagreement with one particularly section of the League's constitution, stating that: "to say [the parliamentary vote] is obsolete will lead many to suppose that it once was useful.
When a by-election was called in Paisley, the Communist League attempted to put this proposal into action, offering to support an SLP candidate that stood on an abstentionist platform.
Tensions between the anarchists and the Marxists within the League had also heightened during the latter half of 1919, with fierce debates breaking out over the theoretical differences that had been present in the organization since the founding conference.