John was clinical dean of the faculty of medicine and dentistry at King's College London from 1988 to 1992 and was president of the surgical section of the Royal Society of Medicine. His skills and knowledge lead to his appointment as surgeon to the Royal Household 1975-1983, Surgeon to HM The Queen 1983-1990 and Serjeant Surgeon 1990-1991. He retired in 1991, and died on May 16, 1999. Dawson Ward at King's College Hospital was named in his honour in 1999.