MB ChB Manch 1946, MD (hon) 1990; MRCP Lond 1948, FRCP 1965.
Longson was educated in Brussels before entering the faculty of medicine at the University of Manchester. After qualifying, Longson was house physician, resident clinical pathologist and resident medical officer at MRI. In 1951, he was appointed demonstrator in physiology at the University of Manchester, and was also honorary medical officer at Barnes Hospital, Cheadle. In 1952 Longson was appointed senior registrar at MRI. In the mid 1950s Longson held research fellowships at Columbia University, New York. He returned to Manchester in 1956 and was senior registrar to Manchester Regional Hospital Board and Salford Hospital Group. In 1958 Longson was appointed senior registrar at MRI and honorary assistant lecturer in physiology at the University. He was later lecturer in clinical endocrinology at the University of Manchester and honorary physician at MRI. Longson was also dean of clinical studies at the University and subdean of postgraduate studies. He was awarded an honorary MD at the University of Manchester in 1990.