Sir Patrick McEwen Forrest was regius professor of clinical surgery at the University of Edinburgh. Pat, as he was known to all, was a giant of British and international surgery, and his contributions to the management of breast cancer were immense. He was born in Lanarkshire, the son of Andrew James Forrest and Isabella Forrest née Pearson, and educated at Dundee High School before studying medicine at the University of St Andrews (University College, Dundee). Following his graduation in 1945, he served as a house surgeon at Dundee Royal Infirmary before being called up for military service as a surgeon lieutenant and medical officer in the Royal Naval Volunteer Reserve, which included foreign service in Singapore. He returned to junior training posts in Dundee before undertaking a Foundation fellowship at the Mayo Clinic (from 1952 to 1953). His resulting experimental research into gastric secretion secured him a masters in surgery with honours. His intellect was recognised by many and his dedicated approach to research led to his being recruited to Sir Charles Illingworth’s distinguished surgical unit in Glasgow where, as a lecturer and later senior lecturer, he completed an MD, again with honours, on pituitary implantation on advanced breast cancer. He was appointed to the chair of surgery at the Welsh National School of Medicine in Cardiff in 1962, where he established a strong department with productive research programmes in the management of both gastrointestinal and breast disease but with increasing focus on the latter area. He succeeded Sir John Bruce to the regius chair of clinical surgery at the University of Edinburgh in 1970 and embarked on a highly successful period of research leading seminal clinical trials on the treatment of breast disease. He founded the British Breast Group in 1965, recognising the importance of collaborative research and conducted many key multicentre trials, which established the evidence base for much of modern breast cancer management. He also appreciated the value of a multidisciplinary approach to the management of breast cancer as well as the benefit to patients of site-specific specialisation in cancer treatment, which has remained the philosophy of Edinburgh surgery. Through his research, his chairmanship of the working group on breast cancer screening for the UK Health Departments, and through the subsequent publication of the Forrest Report (*Breast cancer screening: report to the health ministers of England, Wales, Scotland and Northern Ireland*, London, HMSO, 1986), he was responsible for the introduction of breast cancer screening in the United Kingdom by the time of his retirement from the chair in 1988. His report estimated that the introduction of breast screening would save about 4,000 lives each year and the programme, which he defended strongly, continues with the number of deaths having fallen by a third in the UK, while 75% of women with the disease now expect to live for ten years or more. Having transformed the outcomes for women with breast cancer, he was in great demand as a lecturer and visiting professor internationally. Pat served as president of the Surgical Research Society (from 1974 to 1976) and the Association of Surgeons of Great Britain and Ireland (from 1988 to 1989), but he also had significant international impact and enjoyed productive relationships with academic surgical groups in the United States, where he was an honorary fellow of the American Surgical Association. He enjoyed close links with the Chinese University of Hong Kong, having helped guide the establishment of its medical faculty in 1981, the same year as he was appointed as chief scientist for Scotland, a post that he held until 1987. Following his retirement, he was recognised by being appointed professor emeritus by the University of Edinburgh. He spent three years at the International Medical College in Kuala Lumpur, where he introduced breast screening and served as associate dean. He also enjoyed a productive year at the National Cancer Institute at Bethesda. His achievements were recognised by the award of the McKeown and Lister medals by the Royal College of Surgeons of Edinburgh and of England respectively and he was knighted in 1986 for his services to surgery. Over 20 of his departmental staff and fellows went on the secure professorial appointments worldwide. He edited many books including the first edition of *Principles and practice of surgery: a surgical supplement to Davidson’s principles and practice of medicine* (Edinburgh, Churchill Livingstone, 1985). Pat’s father had been a minister with the Church of Scotland and, following his retirement, he continued his longstanding association with St Giles’ Cathedral, serving as an elder. He played golf enthusiastically although this often served as second best as he committed to sailing regularly on to the Firth of Forth on his boat which was maintained at Port Edgar. Colleagues, trainees and fellows were often recruited to crew his boat but thoroughly enjoyed his warm and generous hospitality. He had married on his return to Scotland in 1955 but sadly his wife Margaret (née Hall) died in childbirth in 1961. In 1964, he married Margaret Steward, an Australian dietitian whom he met on a visit to the metabolic unit in Cleveland, Ohio. Up until Pat’s health declined, he and Margaret were always prepared to welcome friends to their home and extend their hospitality generously. He died on 7 August 2021 at the age of 98 and was survived by Margaret and his three children Susan, David and Anne.