He enlisted in the Union Defence Force in 1942, serving as a stretcher bearer in the Second World War in North Africa and Italy in the 6th South African Armoured Division.
He spent some time serving under Albert Schweitzer at Lambaréné in French Equatorial Africa (now Gabon), and travelled to the United States in 1957–8 under a Carnegie Fellowship, and started to specialise in endocrinology.
He also continued to practise medicine at Groote Schuur Hospital, where he was involved preparing for Christiaan Barnard's first heart transplant operation in 1967.
In July 1967, the Prime Minister John Vorster imposed a banning order under the Suppression of Communism Act which prohibited him from all political and social activity for 5 years.
He worked for the National Medical Health and Research Council at Mill Hill in north London, and at the thyroid clinic at New End Hospital in Hampstead, for four years from 1968.
Meanwhile, he was President of the Royal College of Physicians from 1983 to 1989,[1] publicly disagreeing with the Conservative government's policy of introducing an internal market into the National Health Service.
After the Alder Hey organs scandal came to light in 1999, he courted controversy by arguing for the medical benefits from retaining tissue samples from post-mortem examinations.