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. They both had a similar social background and a keen interest in sports. It was expected that Brotheridge would pursue a career as a professional footballer following the war. They had both served in the ranks and Howard considered him to be a friend. Brotheridge did not initially enjoy an easy relationship with his fellow platoon leaders who all came from a different social background to himself. He was popular with the members of his platoon.