After the war Murphy was only just able to survive on the meagre unemployment benefit he received by selling some furniture and books and with financial support from his mother. However, freed from the constraints of work, he was able to throw himself into full-time activity as chair of the Sheffield Workers’ Committee and assistant secretary of the National Administrative Council of the SS&WCM. He also became active in the Sheffield branch of the Plebs League, which organised study classes among trade unionists, and gave two weekly Labour College lectures on Marxist economics and industrial history. In addition, after being elected an executive committee member of the Socialist Labour Party (SLP), he went on to play a central role in reshaping the party's policy and in conducting socialist unity negotiations with other revolutionary groups that eventually led to the formation of the British Communist Party.

Of major significance during this period of 1919–1920 was his political evolution from syndicalism to communism, as he combined his own wartime shop steward experiences with the events in Bolshevik Russia to develop a new form of revolutionary socialist politics. This involved three main features: an appreciation of the soviet as the chief agency of socialist revolution and the need for the working class to conquer state power; the central role of a vanguard political party; and the relationship between revolutionary socialists and the Labour Party. He also further developed his wartime analysis of the trade union bureaucracy.

THE THEORY OF SOVIET POWER

It was only after the war, in the context of the Russian revolution and revolutionary turmoil throughout Europe, including massive labour unrest in Britain, that the full revolutionary implications of their own wartime practice of independent rank-and-file organisation came to be appreciated by Murphy and the others shop stewards’ leaders. Aided by theoretical developments within the SLP and the BSP, which their own practice helped to promote, the stewards’ leaders initiated a new burst of theoretical activity during the autumn of 1918 which was to extend beyond the concept of rank-and-file independence to the idea of the seizure of state power by the Workers’ Committees, which were now conceived of as embryonic ‘soviets’, the economic and political nucleus of a future workers’ state similar to that which existed in Russia.