The Mark III improved upon the Mark II by providing a three-man turret. Mark III production ended in 1942 after 1,650 had been built. With a possible replacement, the 2-pounder armed Coventry armoured car, on its way, the Mark IV was designed. This put the US 37 mm gun in the turret but at the cost of one crewman. The Coventry was not ordered as a replacement and so production of Mark IV continued, for a total of 2,000, despite its flaws.