For a short time in the storied history of the Centurion Main Battle Tank (MBT), a heavily armed self-propelled gun (SPG) variant was entertained as the FV4005 "Stage 2". This vehicle utilized the existing chassis and hull superstructure of the Centurion MBT mated to a fully-enclosed, 360-degree traversing turret housing a 183mm (7.2") Howitzer main gun (the BL 7.2-inch field howitzer). An earlier attempt saw the Centurion up-gunned with the 183mm weapon (with automatic loader) in a limited-traverse mounting sans the turret and this became the FV4005 "Stage 1" - both forms were related to the earlier FV4004 "Conway" which attempted to up-gun the Centurion with a turreted 120mm L1 weapon to serve while the FV214 "Conquerer" heavy tank was still being developed.
The FV4005 program began in 1951 with development stemming into mid-1955. However, the initiative fell to naught and was ended in 1957. A sole example of the FV4005 Stage 2 went on to be preserved outdoors on the grounds of the famous Bovington Tank Museum in England.
The Centurion roots in the FV4005 Stage 2 were clearly visible with even the side skirt armor retained. The running gear remained six double-tired road wheels to each hull side with the drive sprocket at rear and the track idler at front. The drive sat at front-right the hull with the remaining crew in the boxy turret superstructure - assumed to house the commander, gunner, and at least loader. The turret structure was set at the middle of the hull roof with extensive overhand at the rear to provide the for the necessary ammunition stowage and working space for the gunnery crew. A hinged, rectangular door was set at the rear-facing wall of the turret for crew access. The primary gun armament protruded from the frontal panel of the turret and some barrel overhang was noted. The engine compartment was held at the rear of the hull - the same arrangement as in the Centurion MBT.
Drive power would most likely have remained the Rolls-Royce Meteor of 650 horsepower. Operational range is estimated to be 250 miles with a maximum road speed of 18 miles per hour possible.