The Humber Armoured Car was one of the most widely produced British armoured cars of the Second World War. It supplemented the Humber Light Reconnaissance Car and remained in service until the end of the war. Development The Guy company did not have sufficient production capacity to produce sufficient Guy Armoured Cars as well as other vehicles, so shortly after war broke out the Rootes Group were approached to produce an armoured car – at the time the terminology "Tank, Light (Wheeled)" was used by the Army. Working from the Guy design, Karrier designed a vehicle using as a basis their KT 4 artillery tractor chassis (already in production for the Indian Army) and the armoured body of the Guy Armoured Car. Karrier moved the KT4 engine to the rear and fitted welded bodies and turrets provided by Guy. As it had been based on proven elements, trials of prototypes passed without serious issues and an order for 500 was placed in 1940 and first deliveries made in 1941. The Karrier name was dropped to avoid confusion with the British Universal Carrier tracked vehicle and the vehicles were designated "Armoured Car, Humber Mk 1" using the name of Humber Limited (another member of the Rootes Group) though production was by Karrier at the Luton works of Commer (yet another Rootes company). The first Humbers were more or less identical to the Guy down to the faults in the armour, but this was later rectified. 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. Design The Humber was a rectangular chassis frame with a rear mounted engine. The gearbox was mounted to the front of the engine; it fed a centrally mounted transfer box which distributed power to front and rear differentials. The rigid axles were mounted on leaf springs front and rear with hydraulic dampers. The welded armoured hull was mounted at four points - front, rear and sides - to give some flexibility but with precautions