Upon his return to England, Malone became active in the "Hands Off Russia" campaign, and in November 1919 he officially joined the proto-Communist British Socialist Party (BSP). Malone was soon being elected to the party's leadership through the patronage of Theodore Rothstein. In the summer of 1920, the BSP became the main constituent of the Communist Party of Great Britain (CPGB), and as a result, Malone became the first CPGB MP. He attended the London Communist Unity Convention held 31 July and 1 August 1921, at which he was elected to the new party's governing Central Committee. Malone's sudden conversion to revolutionary politics brought more questions than answers, and its genuineness was questioned. John Maclean claimed that Malone was a counter-revolutionary sent to disrupt the workers' movement, and he refused to speak alongside Malone.