As a development from the Churchill, the Black Prince was a continuation of the line of Infantry tanks, that is slower, heavier tanks intended to operate in close support of infantry. It also was able to work closely with other tanks. The parallel development in British tank design were the Cruiser tanks, which were intended for more mobile operations. A43 was the General Staff Specification number issued in 1943, for an interim tank that would eventually be superseded by a "Universal tank" that would replace both Infantry and Cruiser tanks. The cruiser line led to the Cromwell tank and then the Comet tank. These tanks entered service during the war. While not as heavily protected as the Churchill, the Comet showed the way British tank development was going. This led to the last of the cruiser line and the first of the Universal tanks - the very successful Centurion tank. A larger gun than that carried by a conventional Churchill required a larger turret on a wider turret ring and consequently a widening of the tank hull. The Black Prince weighed around ten tons more than the Churchill so the suspension was modified and the tracks widened by 10 inches to carry the extra load. However, the Churchill's engine was retained, leading to the tank being underpowered and slow, with maximum speeds on roads and cross country. This was so slow that the tank's tactical usefulness would have been limited. Consideration was given to the use of the Rolls-Royce Meteor engine; this would have increased the available power to, but the idea never left the drawing–board. Likewise, plans to fit the Black Prince with the turret from the Centurion were never carried out. By the time the Black Prince prototypes had appeared in May 1945, the Sherman Firefly had proved itself in combat, the Comet tank was in service and the introduction of Centurion was imminent. All these tanks carried the QF 17-pounder or a derivative; all had better mobility than the Black Prince and the Centurion had frontal armour of comparable effectiveness. The Black Prince had become redundant and the project was abandoned. The Black Prince marked the end of the development of the A22F Churchill Mk VII, and the end of the Infantry tank concept in British tank design.
