Docherty's father joined the Fife Communist Anarchist Group, and was also a founding member of the Communist Party in Britain. Docherty herself joined the Communist Party at the age of 18, the youngest age at which she was able to do so, soon after the 1926 United Kingdom general strike. She initially became a member of the Young Communist League, or YCL. During the strike, she was involved in the "Local Councils of Action", which were inspired by the Russian Soviets, and helped coordinate the strike. The miners' defeat in the strike was very influential upon her. The Communist Party provided her with an adult education, during which she was one of two women among 48 men. The other woman in her class was her mother. While still a teenager, she became the literature secretary for the Cowdenbeath branch of the party, and was responsible for the production and sale of a number of weekly newspapers.