FV 214 Conqueror The FV 214 Conqueror , also known as " Tank , Heavy Gun No 1 120 mm Conqueror " was a British Main Battle Tank of the post - war era , sometimes classified as a heavy tank . It was developed as a response to the Soviet Josef Stalin IS - 3 heavy tanks and carried a larger 120 mm gun compared to its peer ' s , the Centurion , 20 - pounder ( 83 . 4 mm ) . Its role was to provide long range anti - tank support for Centurion tanks . They were issued nine to a regiment in Germany ; usually grouped in three tank troops . Description . The gun design was American , the same as used on the US M103 heavy tank ; with separate charge and projectile , as would also be the case in the Chieftain that followed . The charge was not bagged but in a brass cartridge , which offered some safety advantages , but reduced shell capacity to 35 . The armour was very heavy for the time , especially in the front , where it was seven inches ( 178 mm ) in the horizontal plane . Unfortunately , this , along with the weight of the huge turret required to house the large gun and the very large hull volume , made the vehicle very heavy , giving it a relatively low top speed and making it mechanically unreliable . Also , few bridges could support its weight . However , rather like the Second World War Churchill tank , the Conqueror had exceptional terrain handling characteristics and proved to be as capable cross country as the lighter ( and on paper slightly faster ) Centurion tank . One feature of particular note was the rotating commander ' s cupola , which was at the heart of the Conqueror ' s fire control system , advanced for its time . The commander could align the cupola on a target independently of the turret , measure the range with a coincidence range finder , and then direct the gunner on to the new lay mechanically indicated to him by the cupola . In theory , when the gunner traversed to the new lay he would find the target already under his sights , ready to be engaged . Meanwhile , the commander was free to search for the next target . The system may have been inspired by a similar device , without range finder , installed in WWII German Panzer s which was apparently highly successful , but was not repeated in subsequent tanks until an updated electronic version of the same idea appeared in the American M60A2 . Development history . The chassis was from the A45 Infantry Support Tank , started in 1944 shortly after that of the A41 Centurion . After the war the project was relocated to that of the " Universal Tank " design of the FV 200 series . The 200 series was to have used a common hull for all uses ( self - propelled artillery , armoured personnel carrier , three varieties of tank , etc . ) . One tank type was to be the heavy FV 201 of 55 tonnes , armed with an 83 . 4 mm gun . In 1949 it was decided to bring the armament up to 120 mm . As this delayed the project , in 1952 the FV 201 hull was combined with a 17 pounder - armed Centurion Mk 2 turret to give the FV 221 Caernarvon Mark I . Twenty - one were built with the Mk III 20 pounder turret as the Caernavon Mk II . The FV 221 may originally have been intended to be the " Main Battle Tank " member of the FV 201 series , but with the success of the A41 Centurion such a vehicle was no longer required . In either event , the Caernarvon was only used for chassis development work serving in troop trials . In 1955 the first Conqueror was produced . Twenty Mark 1 and 165 Mark 2 Conquerors were built including conversions of Caernavon MkIIs . Production continued until 1959 . It had lost much enthusiasm once the Centurion was upgraded to an L7 105 mm gun . Surviving Vehicles . " This is an incomplete list . " In the United Kingdom , Conqueror tanks are displayed at the Bovington Tank Museum , and the Land Warfare Hall of the Imperial War Museum Duxford . Other tanks are in the collections of the Musée des Blindés in France , the Royal Museum of the Army in Brussels and the Kubinka Tank Museum , Russia . One is privately owned in the United States as part of the Littlefield Collection . There are also two MkII ARVs at the Military History Museum on the Isle of Wight . One is shown in the photograph on the right . The second vehicle is off picture to the right . Both are outside and are in a similar condition . A MkII ARV is held by the REME Museum of Technology , although it is not on display . There used to be a Conqueror at Base Vehicle Depot Ludgershall - a gate guard named William .