Born into a medical family on 13 May 1912 in Strichen, Aberdeenshire, John Stephen's father was John Herbert Stephen, a general practitioner. His mother, Isabel née Mackie, was a teacher and the daughter of an engineer. He was educated at Aberdeen Grammar School and Aberdeen University, where he was house surgeon. He was subsequently an assistant lecturer in the department of anatomy at Edinburgh University. In 1937, he went to London to work in the London County Council Medical Service, at first at St Pancras Hospital and then at St Giles Hospital, Camberwell. Prevented by previous tuberculosis from joining the armed services, he spent the war as the senior resident surgeon at Dulwich Hospital, dealing with air raid casualties. In 1948, he was appointed surgeon to the Paddington General Hospital, later incorporated into St Mary's, and in 1955 was appointed surgeon to the varicose vein clinic - a rather pointless title since, in fact, he had his own surgical wards where his skill in intestinal surgery and hepatic resection became legendary. On the retirement of Sir Arthur Porritt, he found himself the senior surgeon at St Mary's. He was a Vice-President of the section of surgery of the Royal Society of Medicine. He wrote extensively, mainly on resection of the liver. In 1938, he married Mary Milne. They had a son, John, who became a surgeon, and a daughter, Ruth, who was a dentist. There are four grandchildren - Helen, Catherine, William and Alice. He died on 17 May 2001.