Sidney was educated at Cathedral King’s School. Worcester; at Downing College, Cambridge, and at St Thomas’s Hospital. London, qualifying M.B., B.Ch. in 1904 and M.D. in 1909. In 1911 he gained a diploma in public health. Previous to this he has served as a combatant in the 1st Bn. Suffolk Regiment in the South African War from 1899 to 1901. Sidney then joined the Special Reserve of the R.A.M.C. He joined the 1st Field Ambulance on 6th August 1914 in Aldershot, then entered the war, with the unit, on 18th. He was awarded the Distinguished Service Order on the occasion he “Went with a party of stretcher-bearers across ground swept by rifle and shell fire to Langemark Village, and removed 11 wounded men.” He served with the 1st Field Ambulance up until 17th March 1916, when he proceeded for duty at Rouen, becoming the Medical Officer, No 5 Infantry Base Depot there. From March 1917 he served as a Senior Medical Officer in Paris; from June 1917 he was 2nd in command of the 1/2nd East Lancashire Field Ambulance; and in October 1917 he was 2nd in command of the 24th Field Ambulance, gaining the rank of acting Major with this unit in January 1918. In June 1918 he became the Officer Commanding the 31st Motor Ambulance Convoy. Sidney was the son of John A Steward, J.P.