BSc Edin 1958, MB ChB 1960, PhD 1963; FRCP Edin 1976.
Mawer was educated at Blackpool Grammar School and Edinburgh University, where he studied pharmacology and medicine. He worked in the departments of pharmacology and therapeutics at Edinburgh before joining the department of pharmacology at the University of Manchester as senior lecturer in 1966. In 1974, Mawer was promoted to the chair of clinical pharmacology. He had been made honorary consultant physician to United Manchester Hospitals in 1969. Mawer specialised in clinical toxicology and the monitoring of drug use. Mawer retired, probably in the 1980s, and was made emeritus professor. He was also visiting consultant to the David Lewis Centre for Epilepsy, and was a member of the British Pharmacology Society and the International League Against Epilepsy.