Born in 1884 at Boston, Lincolnshire son of William Gilliatt, he received his medical training at the Middlesex hospital, where he was an outstanding student. He won the Hetley clinical scholarship, the junior Broderip scholarship, the Leopold Hudson scholarship and the Lyell gold medal and scholarship. After qualification in 1908 he held house appointments at the Middlesex Hospital as house physician, house surgeon, obstetric house physician and, finally, obstetric registrar and tutor. He was elected to the staff of King's College Hospital in 1916 retiring as senior gynaecologist in 1946, having been a member of the committee of management from 1932 onwards and, in 1945, vice-chairman. His other appointments included those of gynaecologist to St Saviours's Hospital, Maudsley Hospital and the Bromley Cottage Hospital. He was an examiner for the Universities of Cambridge, London and Bristol and for the Conjoint Board. For more than twenty years he had been gynaecologist to the Royal Household and, in 1952, became gynaecologist to the Queen attending at the births of Prince Charles and Princess Anne. He also attended the Duchess of Kent at the births of her three children. In 1954 he was elected president of the Royal Society of Medicine. He was a brilliant clinician and a skilful surgeon and combined these attributes with great ability as a teacher by writing and by the spoken word. An ideal chairman of a committee, he was eminently fair but could be ruthless if necessity arose. He was President of the College of Obstetricians and Gynaecologists from 1946 to 1949, when his common sense and dignity combined with his administrative ability were of the greatest value. A simple and abstemious man he was rather reserved, the result not of pride but of an essentially shy nature. He married Dr Anne Louise Kann, daughter of John Kann of Lyne, Surrey, by whom he had a son, now on the staff of the National Hospital, Queen Square, and a daughter, at one time secretary to Sir Winston Churchill. His wife was an anaesthetist to the Royal Free and Elizabeth Garrett Anderson Hospitals before her marriage. He died suddenly on 27 September 1956 as a result of a motoring accident at Long Cross, Chertsey.