With a yearning to learn and 'an urge for the distant', Petroff moved to Odessa in 1898 where he informally attended university classes and organised his first workers' study circle[1] and in 1901 joined the (illegal) Russian Social Democratic Labour Party (RSDLP), spending several stints in prison for his activities.
It was there, in Glasgow-Clydebank, he wrote that he linked up with organised Social Democratic Party and several significant figures, although his political connections with Maclean at this time now appear from Petroff's own account appear to have been considerably overstated.
[2] The SDF reformed as the British Socialist Party (BSP) in 1912, and Petroff was elected to its first standing orders committee, alongside Duncan Carmichael, E. C. Fairchild and C. T. Douthwaite.
[2] An opponent of World War I, he gave talks which attracted large crowds and influenced members of the Clyde Workers Committee (CWC).
Nonetheless, he wrote articles on the progress of the movement for Nashe Slovo and Berner Tagwacht, raising its profile among socialist anti-war activists across Europe.
He was sympathetic to Trotsky's Left Opposition, and resigned from the Bolshevik Party in 1925, but remained active in the German communist movement until the Nazi rise to power.