Coming out of a General Staff request in 1941 to investigate fitting high velocity guns on tanks. Neither the Churchill nor Valentine could mount a turret with a high velocity gun larger than the 6 pounder, but it was proposed that a fixed superstructure could carry a larger gun with limited traverse. Vauxhall was provided with 100 guns and given the task of producing the vehicle. The pilot vehicles were ready for testing in early 1942 and found to be satisfactory, but progress with the 17 pounder Challenger cruiser tank and refocussing on a general purpose role (and 75mm gun) for the Churchill led to a reduced order. A fixed 88 mm (3.5 in) thick superstructure with the gun in a ball mount was installed on the chassis of a Churchill. The gun was an otherwise obsolete 3 inch 20 cwt anti-aircraft gun. Fifty were built in 1942, but none are known to have been used in combat as the 17 pounder anti-tank gun gave the British the necessary firepower
