Complex sentence: He joined the Labour Progressive Party a few years after his expulsion, and in 1949 accused social democratic parties such as the CCF of being traitors to the working-class, and propping up the existing capitalist order.
Split into simpler sentences: He joined the Labour Progressive Party a few years after his expulsion from the CCF. In 1949, he accused social democratic parties such as the CCF of being traitors to the working-class, and of propping up the existing capitalist order.