Platoon Sergeant Major (PSM) was an appointment in the British Army in the short-lived rank of Warrant Officer Class III (WOIII), created in 1938. The Platoon Sergeant Major, and his cavalry counterpart, the Troop Sergeant Major, were part of an experiment in giving experienced NCOs command of units formerly reserved for commissioned officers (platoons and troops). The experiment was not considered a success, and no promotions were made to the rank after 1940: most existing WOIIIs were commissioned as lieutenants.