The infantry tank was a concept developed by the United Kingdom and France in the years leading up to World War II. Infantry tanks were designed to support infantrymen in an attack. To achieve this, the vehicles were generally heavily armoured to allow them to operate in close concert with infantry even under heavy fire. The extra armour came at the expense of speed, which was not an issue when supporting relatively slow-moving foot soldiers. Once an attack supported by infantry tanks had broken through heavily defended areas in the enemy lines, faster tanks such as cruiser or light tanks were expected to use their higher speed and longer range to operate far behind the front and cut lines of supply and communications. The infantry tank was superseded by the "Universal Tank" concept which could adequately perform the roles of both infantry and cruiser tank, as represented by the Centurion which replaced both the Churchill and any medium or cruiser tanks then in service. This led to the main battle tank. Background The experimental armoured formations of the British army were mostly equipped with the Vickers Medium Tank Mk I and Medium Mk II, which were judged obsolete by the 1930s; most of the vehicles were at the end of their mechanical life. It was impractical to build more because their road speed of only was too slow for manoeuvre warfare and their armament of a 3-pounder gun lacked the power to penetrate newer foreign tanks. By 1931, experience with the Experimental Mechanized Force led to the report of the Kirke Committee and specifications for three types of tank, a medium tank with a small-calibre anti-tank gun and a machine-gun, a light tank armed with machine-guns for reconnaissance and to co-operate with medium tanks by engaging anti-tank guns. A close support tank armed with a gun firing high explosive and smoke shells to give covering fire for tank attacks was also specified. The Wall Street Crash of 1929 and the Great Depression led to big reductions in the funds made available for the army. Money spent on tracked vehicles fell from £357,000 in 1931–32 to £301,000 in the year 1932–33 and exceeded the 1931 figure only in 1934–35. In May 1934, Lieutenant-General Hugh Elles was appointed Master-General of the Ordnance and Brigadier Percy Hobart, the Inspector, Royal Tank Corps, asked Vickers to design a tank for infantry co-operation, that could