The need for economy in the design and production of the A11, which was too small for a radio, led to work on a successor, the A12, Infantry Tank Mk II in 1936. Capable of , the A12 was still slow but had of armour, making it almost invulnerable to tank guns and standard foreign guns like the German 37 mm Pak 36 anti-tank gun. The tank had a four-man crew and a turret big enough for a radio and an Ordnance QF 2-pounder high-velocity gun, firing solid projectiles capable of penetrating all 1939–1940 German tanks. Vickers and government factories could not take on the work and it was farmed out to a civilian firm, which lacked experience, designers and draftsmen. It took until 1939 to bring the A12 into production as the "Matilda II" and it had not gone into service when the war began, only having been delivered. When the Matilda was supplied to Army Tank Battalions it was an effective tank in the Battle of France and in the Western Desert Campaign, where it outclassed Italian tanks and was effective against standard Italian and German anti-tank guns from 1940–1941 but was later found to be too slow for the fast tempo that German panzer units could achieve and unable to engage the more powerful German anti-tank guns from long range with high explosive shells.