and reduce the weight of the design. However, contrary to normal practice, the Ordnance Department had placed an order for the original T9 design in April 1942, before the T9E1 models were delivered in November 1942; 500 were ordered in April and this order rapidly increased to a total of 1900, with deliveries to begin in November. However, production difficulties and design changes caused this date to be delayed several times, and it was not until April 1943 that production of the T9 actually began. Production of the T9 peaked at 100 tanks produced per month between August 1943 and January 1944; however, this number rapidly declined when the results of the British and American testing programmes were reported to the Ordnance Department, and only 830 T9s were ever produced. The faults discovered with the design led to the Ordnance Department giving it the specification number M22, but classing it as 'limited standard'. No American combat units were equipped with the tank, although some of those produced were used for training purposes and two experimental units were formed and equipped with Locusts. The 151st Airborne Tank Company was formed on 15 August 1943, despite concerns that there would be insufficient transport aircraft to deliver the unit into battle, and the 28th Airborne Tank Battalion was also formed in December of the same year. However, neither unit saw combat, due to the US Army's lack of interest in using them in an airborne capacity. The 151st Airborne Tank Company remained in the United States, shuttling from base to base throughout the war, and the 28th Airborne Tank Battalion was refitted with conventional tanks in October 1944. Some 25 Locusts were ordered in April 1944 for use in the European Theater of Operations, and delivered by September; although a small number were sent to the United States Sixth Army Group in Alsace, France, for testing, they were never used in combat. However, the British still required the M22 as a replacement for the Tetrarch and the first prototype Locust was shipped to Britain in May 1942 for testing, followed by the second prototype T9E1 in July 1943. Although they were of the opinion that the M22 possessed a number of faults, the War Office believed it would perform adequately as an airborne tank. Thus the tank received the official title of "Locust" and 260 were shipped to Britain under the Lend-Lease Act.