Born in Tottenham he was educated at Tottenham Grammar School and the University of East Anglia where he joined the CPGB and met his first wife Anne. They moved to Yorkshire where he was Secretary of the CPGB in Barnsley. Lefley belonged to the Straight Left faction within the Communist Party of Great Britain. Lefley remained general secretary of CND until 1994 when the post was abolished, and the anti-nuclear movement declining, towards the end of the Cold War. He remains a politician and Union activist and is currently Hedteacher of a Pupil referral Unit in London.