of 20 of the tanks to the USSR under the Lend-Lease Act depleted the number available for use by airborne forces, as did the loss of several more during Operation Ironclad, the invasion of Madagascar. A Royal Armoured Corps report issued in December 1942 stated that approximately 50 Tetrarchs were available for use. In a memorandum, dated January 1943, by Major General George F. Hopkinson, commander of the 1st Airborne Division, Hopkinson complained that he had been informed that 70 of the tanks were available, whereas only 50 actually remained, with no reserves to replace those lost in combat. This lack of sufficient replacement reserves, combined with a War Office report that some 287 airborne tanks would be required for the 1st Airborne Division and an unnamed airborne division to be formed in India, led to the Tetrarch's eventual replacement by the US M22 Locust. Performance A number of design faults of the Tetrarch were revealed through its operational use. Its size limited the possible crew to three, a driver in the hull and a gunner and commander in the turret, resulting in too few crew members to operate the Tetrarch effectively. The gunner or commander, in addition to his own duties, had to act as loader for the 2-pounder, which caused delays in combat. A report on the tank written in January 1941 stated that as the commander had to both fight and control the tank, controlling a troop of Tetrarchs during combat would be almost impossible. Problems were also found with the Littlejohn adaptor fitted to the 2-pounder to increase its range and penetration power; after they had been fitted the adapters could not be removed, and could only fire specially designed armour-piercing rounds, which took time to manufacture. The War Office also considered the Tetrarch's cooling system faulty, making the tank unsuitable for service in hotter climates, such as the Middle East and North Africa. Operational history Lend-lease The first Tetrarchs were delivered to the Army in November 1940, and were initially deployed with the 1st Armoured Division (which was being refitted after losing the majority of its previous tanks during the Battle of France) and the newly formed 6th Armoured Division. However, the faults discovered with the Tetrarch cooling system precluded them from being integrated into units that were sent to the Middle East to participate in the North African Campaign. Shortly after, all light tanks