Harold Daintree Johnson was born in London on 26 May 1910, the second son of Sir Stanley Johnson, a solicitor and one-time Conservative MP for Walthamstow. His mother, Edith Heather, was the daughter of a professor of mathematics. After education at Westminster School he entered University College London to train as an engineer. He then changed to medicine at Christ's College, Cambridge, before moving to St Thomas's Hospital where he graduated in 1936. He was casualty officer and house surgeon at his teaching hospital before travelling for a while as a ship's surgeon. He returned to St Thomas's as a surgical registrar, completed the FRCS in 1940 and was acting resident assistant surgeon before being appointed surgical first assistant at the London Hospital in 1942. The following year he joined the RAMC as a surgical specialist and served with the 224 and 225 Parachute Field Ambulances, in the 6th Airborne Division in north-west Europe. He was demobilised with the rank of Major and became lecturer in surgery at the Royal Postgraduate Medical School, always recognising his indebtedness there to Ian Aird and Richard Franklin, and to B C Maybury at St Thomas's Hospital. Continuing as a senior lecturer at Hammersmith, he was also appointed surgeon to the Royal Free Hospital and Hampstead General Hospital and consultant general surgeon to the National Throat Nose and Ear Hospital. He had held a Leverhulme Scholarship at the Royal College of Surgeons in 1948 and later served on the Court of Examiners for six years as well as examining in surgery for the University of London. He was a keen and active member of the British Society of Gastroenterology for many years. Before entering medicine, as a young man with engineering training, Johnny Johnson, as he was known, had built and raced his own cars at Brooklands. He had conceived the idea of the clover-leaf road crossing and the safety binding for skis, both of which are now in general use. His earlier knowledge of engineering and fluid mechanics enlightened much of his approach to surgery. At Hammersmith after the war he and Ian Orr did some of the earlier truncal vagotomies for duodenal ulcer and, later, vagotomy with antrectomy. He was also interested in the classification of gastric ulcer, the mechanism of the cardia and the problems of the swollen leg, work which was largely undertaken after his early retirement from clinical surgery in 1965, due to failing sight and associated ill-health. That was shortly after he had taken the MD and he completed his MCh three years later. It was during this time that he published his two books: *The cardia and hiatus hernia* and *The swollen leg*, supported in his researches by the Medical Research Council and the Wellcome Trust. Harold Johnson very bravely and characteristically adapted himself to his restricted life, but, with one of the most original minds and considerable enthusiasm, he put his talents and remaining powers to good use in what was to be one of the most productive periods of his life. He was always a quiet and reserved man who later inspired the admiration and affection of his many loyal friends. He had married Margaret Dixon, in 1944 and they had two sons, one of whom predeceased him. For twenty years he had enjoyed himself as a part- time farmer and this, together with physics and mathematics, were his main hobbies. When he died on 2 April 1980, he was survived by his wife and remaining son.