[2] The group began working on the European Marxist Review and publishing Red Flag.
In the early 1970s, the party suffered a major split, with supporters of Dave Douglass leaving to form the Socialist Union (Internationalist).
He was the author of a number of works with an unconventional slant; he tried to create a synthesis of Trotskyism and Ufology.
His most prominent thesis from this perspective was Flying saucers, the process of matter and energy, science, the revolutionary and working-class struggle and the socialist future of mankind (1968).
Posadists believed that extra-terrestrials visiting earth in flying saucers must come from a socially and scientifically advanced civilisation to master inter-planetary travel and that the working-class should welcome the alien invaders as their liberators.