The Light Tank (Airborne) M22 or Locust was an American-designed airmobile light tank which was produced during World War II. The Locust began development in 1941 after the British War Office requested that the American government design a purpose-built airborne light tank which could be transported by glider into battle to support British airborne forces. The War Office had originally selected the Light Tank Mark VII Tetrarch light tank for use by the airborne forces, but it had not been designed with that exact purpose in mind so the War Office believed that a purpose-built tank would be required to replace it. The United States Ordnance Department was asked to produce this replacement, which in turn selected Marmon-Herrington to design and build a prototype airborne tank in May 1941. The prototype was designated the Light Tank T9 (Airborne), and was designed so that it could be transported underneath a Douglas C-54 Skymaster transport aircraft, although its dimensions also allowed it to fit inside a General Aircraft Hamilcar glider.
After a series of modifications were made to the initial prototype, production of the T9 began in April 1943. It was significantly delayed, however, when several faults were found with the tank’s design. Marmon-Herrington only began to produce significant numbers of the T9 in late 1943 and early 1944, and by then the design was considered to be obsolete; only 830 were built by the time production ended in February 1945. As a result, the Ordnance Department gave the tank the specification number M22 but no combat units were equipped with it. However, the War Office believed that the tank would perform adequately despite its faults, so the tank was given the title of “Locust” and 260 were shipped to Great Britain under the Lend-Lease Act. Seventeen Locusts were received by the 6th Airborne Armoured Reconnaissance Regiment in late 1943, but mechanical problems led to the tanks being withdrawn in favour of the Tetrarchs previously used by the regiment.
In October 1944 however, the remaining Tetrarchs of the regiment were replaced by Locusts and eight were used duringOperation Varsity in March 1945. The tanks did not perform well in action; several were damaged during the landing process and one was knocked out by a German self-propelled gun. Only two Locusts were able to reach their planned rendezvous point and go into action, occupying a piece of high ground along with an infantry company. The tanks were forced to withdraw from the position after several hours however, because they attracted artillery fire that caused the infantry to suffer heavy casualties. The Locust never saw active service with the British Army again and was classified as obsolete in 1946. A number of Locusts were used by foreign militaries in the post-war period however; the Belgian Army used Locusts as command tanks for their M4 Sherman tank regiments, and the Egyptian Army used several company-sized units of Locusts during the 1948 Arab–Israeli War.