Born at Kensington on 21 December 1873, the son of a Chancery barrister, he was educated at Clifton and King's College Hospital, where he was captain of the Rugby XV in 1895-96, and also rowed in the Hospital fours and eights. Immediately after qualifying he was commissioned in the 13th Imperial Yeomanry and spent two years on active service in South Africa. On 31 May 1900 the regiment of 420 troopers, all former public school boys, with whom he was serving as Surgeon-Captain, was rushed by the Boers; they had been surrounded for four days in barren kopjes and had spent their ammunition. He was left with 75 dead and about 150 wounded; the rest were marched away as prisoners into the darkness. After the war he transferred to the Colonial Medical Service and spent six months "tramping the tropical forests of southern Nigeria" with the Hausa troops of the Aro Field Force during a local campaign; here he was wounded in the hand, and contracted malaria "and other unknown organisms", and possibly the beginnings of the traumatic osteoarthritis which crippled him in old age. Hadley settled in practice at Sheffield, where he was appointed assistant surgeon to the Royal Infirmary. When the RAMC Territorial Force was formed in 1908 he was commissioned as a Major, and raised and commanded the 3rd West Riding Field Ambulance. He also played tennis for Yorkshire. Anxious to live in a warmer climate, on account of his malaria and incipient arthritis, Hadley emigrated to Western Australia in 1912, becoming surgeon to the Perth Hospital and building up a leading practice in succession to Earle Newton FRCS During the war of 1914-19 he commanded the 8th Base Hospital with the rank of Lieutenant-Colonel, Australian Army Medical Corps. He was subsequently surgeon to the Repatriation Hospital at Perth, was created MBE in 1920, and promoted full Colonel on his retirement from the service. Hadley was a founder of the Royal Australasian College of Surgeons in 1926, and a member of the original convocation of the University of Western Australia. He served on the Medical Board of the State, and was a life member of the British Medical Association, serving on its Federal Council in Australia; he also was a life member of the WA University Rugby Club. He retired from practice in 1933 and bought a farm of 14,000 acres of wood and grassland, Riversdale on the Frankland River, which carried 5000 merino sheep; he greatly enjoyed this large-scale pastoral life, mostly spent on horseback in the big paddocks, for he had always been a keen horseman. He sold this property in 1949, dividing it into seven 2000-acre farms for veterans of the second world war. He returned to Perth, where he was senior consultant surgeon to the rebuilt Royal Perth Hospital. He was particularly interested in the Medical School which opened in 1956, presented sporting trophies for competition and left a generous bequest for the School's endowment. He died at Perth on 22 December 1961, the day following his 88th birthday; his wife, Dorothy Glyn Watkins, and son had died before him. In his later years he found recreation in water-colour sketching and kept in touch with old colleagues in England. Hadley was one of the last surgeons to have known Lord Lister, and published in the *Annals* of the College in 1958 (vol 22, p. 279) his memories of Lister's visits to the operating theatre at the old King's College Hospital, while he was house surgeon to Sir Watson Cheyne in 1899. There is a portrait photograph at the Royal Australasian College of Surgeons.