During World War II the British were looking for a purpose-built airborne light tank to replace the Tetrarch light tank but decided not to produce the tank in Britain due to a lack of production capacity. Instead, the American government was approached with a request that it produce a replacement for the Tetrarch. This request was made by the British Air Commission in Washington, D.C., with a proposal calling for a tank of between and to be developed, this being the maximum weight the War Office had decided could be carried by current glider technology. The United States Ordnance Department was given the task of developing the proposed tank, and in turn, requested designs from three American companies: General Motors, J. Walter Christie and Marmon-Herrington. The design offered by Christie in mid-1941 was rejected as it failed to meet the specified size requirements, as was a modified design the company produced in November. At a conference in May 1941, the Ordnance Department chose the Marmon-Herrington design and requested that the company produce a prototype tank, which was completed in late 1941; it was designated the Light Tank T9 (Airborne) by the company and the Ordnance Department and later designated M22.