Stephen was educated at Mr Hall's School at Potters Bar, Herts; at Framlingham, and Harrow; and at St Mary's Medical School, qualifying M.R.C.S. (Eng), L.R.C.P. (Lond) in 1906. He gained a commission within the Medical Services at the rank of Lieutenant, on 28th January 1907. He saw service in Somaliland from 1909 - 1910, and on 28th July 1910 was promoted to Captain. From 1910 - 1914 he served in Jamaica. Stephen entered the war in France on 15th August 1914. He was taken prisoner during the retreat from Mons, and was held, along with 13 other British medical officers at Halle. On 10th February 1915, he along with Major Fry, Captains Priestley, Sutcliffe, Vidal, and Lieutenant Lauder, volunteered to go to Wittenberg camp, Saxony to provide medical care to prisoners suffering with typhus. A typhus epidemic had broken out in the camp in December 1914, whereupon the German staff, both military and medical, precipitately left the camp. Stephen became sickened and died of typhus shortly after Major Fry and Capt Sutcliffe. His services in the POW camp was brought to notice on 10th January 1919. Stephen was the only surviving son of George Purdey (M.R.C.S., Aural Surgeon to St Mary's Hospital, London and for 15 years Dean of the Medical School) and Pauline (By-the-Brook, Mortimer West End, and daughter of Robert Faulder White) Field; and the husband of Margaret (nee Price) - married in London, they had two children.