The son of a psychiatrist Yellowlees was educated at Stowe School and University College, Oxford, which he entered after serving as an RAF pilot from 1941-45. Qualifying at the Middlesex Hospital in 1950 he soon became a medical manager there and on several other hospital boards before being seconded to the Ministry of Health in 1963, rising to become Sir George Godber’s deputy in 1967 and Chief Medical Officer (CMO) in 1973.
The post of CMO has always been a challenging one, being the conduit between government and the medical profession, politicians often regarding the CMO as always being pro-doctors, whilst doctors often saw the CMO as a puppet of government. His time as CMO was exceptionally difficult. He oversaw the rationalising of medical advice to government departments – the Home Office with the prison medical service, the Department of Education and the Ministry of Food and Agriculture. During his time the new specialties of accident and emergency medicine and community medicine came into being, legislation on lead in petrol was passed and the WHO announced the eradication of smallpox.
His concern about the long hours being worked by doctors led Yellowlees to propose reduced working hours, more consultants and more opportunities for young women doctors to remain in medicine whilst raising families.
In spite of a myocardial infarction in 1972 he refused the offer of a Co-CMO as proposed by Godber, often attended all-night negotiations and successfully struggled to hold the NHS together in spite of threatened industrial action by doctors ( the BMA collected 16,000 undated resignations) and frustrated ancillary staff. He oversaw the most radical reorganisation of the NHS, worked with several political masters of Conservative and Labour governments, and left the Department in 1983 to work for a year in the Ministry of Defence on a new structure for doctors in the armed forces. This was then followed by work for the WHO leading the team that successfully negotiated with Turkey and Bulgaria for the provision of healthcare for Bulgarian refugees.
He was a council member of the Medical Research Council for 9 years, of the General Medical Council for 12 years, of the BMA for 4 years and of the British Nutrition Foundation for more than 20 years. He will be remembered by friends and colleagues as a modest, considerate, gentle-mannered man with a wonderful sense of humour, richly deserving of the knighthood and academic honours he received.
He is survived by his second wife, Mary and the three children of his first marriage, to Sally.