 Brotheridge was commissioned into the Oxfordshire and Buckinghamshire Light Infantry in July 1942.Brotheridge first met Major John Howard at Slade Barracks, Oxford and Howard was to recommend him, whilst he was a corporal, to join the Officer Cadet Training Unit (OCTU).Later at a conference in Bournemouth he advised Howard, who was seeking to recruit him as a platoon commander, that he would join D Company, following completion of his OCTU training.