Born in 1903 eldest son of William Bell Allen, a Sydney manufacturer who had served in the Boer War, and his wife Edith Mary Chatteris, a young English actress playing in Sydney, he was educated at Scots College and Cranbrook School. He went up to Sydney University, living in St Andrew's College. As a postgraduate he spent three years in England, serving in hospital house appointments and obtaining the Fellowship. He returned to Australia in 1928 and became medical superintendent of the Royal South Sydney Hospital. In the early thirties he set up in practice in Macquarie Street having become honorary surgeon to the Royal South Sydney Hospital and the Eastern Suburbs Hospital, where he was honorary secretary and later president of the medical board. He was a deft and rapid operator, and an exponent of early post-operative ambulation. His techniques were often original and ingenious but, as he was not attached to a teaching hospital and wrote little, most of his ideas perished with him. He was a notable athlete and horseman, playing polo in a team captained by his father, and was medical officer to the Pony Racing Club. He served for many years as president of a leading squash-rackets club, and cultivated a garden filled with rare, exotic and beautiful plants. He was a man of diverse talents with a rare facility for friendship. Allen died on 3 November 1964, survived by his widow and son.