In 1915, during the First World War he enlisted in the Royal Scots Greys and trained in England while applying for a commission as an officer. After commissioning in 1916 he was posted to the staff of the British Military Attaché at Petrograd (as his birth city was then renamed) until 1918. During that period he witnessed the development of the 1917 Revolution which ruined his father who escaped Russia to exile in England having been allowed out through being identified with the (already dead) British socialist Keir Hardie.