[3] He served as the election agent for party leader Harry Pollitt's unsuccessful campaign in the 1930 Whitechapel and St Georges by-election,[1] then in 1931 was appointed as the CPGB's representative to the Profintern.
[6] Meanwhile, matters came to a head over his political views after party theoretician Rajani Palme Dutt wrote in support of Mahon, but Pollitt was able to manoeuvre the party into dissolving the Minority Movement and refocusing on work in the existing trade unions.
[7] With the Minority Movement no longer in existence, Mahon found a role as Industrial Organiser for the London District of the CPGB.
[1] In 1937, he served as Political Commissar for the British Battalion in the Spanish Civil War, but soon returned to London.
[5] In 1947, he replaced Ted Bramley as District Secretary,[5] and was also elected to the party's Executive Committee for the first time.