Born in Earls Barton, Northamptonshire, Barker moved to Leyton in London in 1878 to become an assistant schoolmaster and joined the National Secular Society.
Barker gained the support of the majority of the Stratford branch of the Secular Society, but failed to influence its national politics.
Barker and Lane set up a new group, the Labour Emancipation League, which in 1884 merged with H. M. Hyndman's organisation to form the Social Democratic Federation.
He appears to have left around the same time as Lane, at the end of the decade, and by 1895 was active in the Anarchist Communist Alliance, an organization whose manifesto was written by Max Nettlau.
He appears to have become active in the National Secular Society again, and his partner Ella Twynam wrote several pieces for them.