An engineering draughtsperson, Yates became an active trade unionist in Leith, Scotland, and joined the Social Democratic Federation (SDF).
By 1898, he was identified as a member of the left wing of the party, and began lecturing alongside James Connolly.
[2] Becoming a convinced supporter of industrial unionism, Yates argued alongside Connolly for the SDF adopting the policies of Daniel De Leon.
[3] In 1903, he wrote an article in Connolly's paper, The Socialist entitled "The Official SDF", which was critical of the organisation's Executive.
[4] In September 1904, Yates resigned his position, claiming that he was unable to edit the paper while holding down a full-time job.