Comet tank The Tank , Cruiser , Comet I ( A34 ) was a British cruiser tank that first saw use near the end of World War II . It was designed to provide greater anti - tank capability to Cromwell tank squadrons . It was armed with the 77mm HV which was effective against late war German tanks and a superior weapon to the 75mm gun of the Panther when firing APDS rounds . As a development of the Cromwell , it was an interim design before the Centurion tank . The Comet saw post World War II combat during the Korean war , and remained in British service until 1958 . Comets sold to other countries continued in some cases to operate into the 1970s . Design and development . Combat experience against the Germans in the Western Desert Campaign demonstrated to the British many shortcomings with their cruiser tanks . Hence a request was made in 1941 to the Nuffield Organisation and Leyland Motors Ltd for a new heavy cruiser tank that could achieve battle superiority over German models . For reasons of economy and efficiency , it had to use as many components as possible from the current A15 Cruiser tank Mk VI Crusader tank . The initial designs submitted were the A24 Cruiser Tank Mk VII Cavalier tank from Nuffield powered by a Nuffield - Liberty L - 12 engine and the A27L Cruiser tank Mk VII Centaur tank from Leyland , which was also powered by the Liberty L - 12 but would be able to use the more powerful Rolls - Royce Meteor when it became available . The Cruiser tank Mk VII ( A27M ) Cromwell was the third parallel development to the Cavalier and Centaur . The Cromwell ' s Meteor engine proved to be very reliable and gave the Cromwell good mobility , but some problems did appear . The tank was prone to throwing its tracks if track tension was not maintained properly or if it turned at too high a speed or too sharply . There were also some problems with suspension breakage , partly due to the Cromwell ' s high speed . A 17 pounder version of the Cromwell , the A30 Cruiser Mk VIII Challenger tank , was under development . To handle the large gun , the Cromwell hull had to be lengthened and a large turret set on top . Due to the slow production of Challengers , the Sherman Firefly ( a Sherman tank fitted with the 17 pounder gun ) conversion received official support . Until the Challenger was available , one Firefly would be issued to each troop of Cromwells ( giving three Cromwells and one Sherman Firefly ) ; but this was unsatisfactory due to the different maintenance requirements and associated supply complication of two tank models , as well as the performance difference between Cromwell and Sherman . With the A34 ( the General Staff specification ) , later named Comet , the tank designers opted to correct some of the Cromwell ' s flaws ( the track shedding and broken suspension problems ) and enhance the Cromwell ' s main strengths , low height and high speed . Originally , it had been expected that the tank would use a new gun from Vickers : the " High Velocity 75mm " . However , as designed , the gun would not fit into the turret size available . So the gun was changed to a different gun , the " 77mm HV " . This gun used the same calibre ( 76 . 2 mm ) projectile as the 17 - pounder but the shell casing was from the older QF 3 inch 20 cwt anti - aircraft gun loaded to higher pressures . The resulting round was completely different to 17 - pounder ammunition . It had a lower muzzle velocity than the 17 - pounder but the ammunition was much more compact and more easily stored and handled within the tank . This made it possible to mount the gun on a smaller turret ring - the Challenger turret had been so large to allow space for two loaders - without making the hull wider . Several other improvements were made : armour protection was increased , the hull and turret were welded with a cast gun mantlet , ammunition was stored in armoured bins , the suspension was strengthened , return rollers were added and the turret was electrically traversed ( a design feature taken from the Churchill tank ) , with a generator powered by the main engine rather than the hydraulic system of the Cromwell . Armour on the Comet ranged from 32 mm to 74 mm on the hull , while the turret was from 57 to 102 mm . The Comet tank ' s top speed was limited from the Cromwell ' s 40 + mph to a slower , but respectable to preserve suspension and engine components and to reduce track wear . The mild steel prototype was ready in February 1944 and entered trials . Although concerns about the hull gunner and belly armour were put to one side ( to avoid redesign ) , there was still sufficient delay caused by minor modifications and changes that production models did not begin to be delivered until September 1944 . Intended to be in service by December 1944 , crew training was delayed by the German Ardennes Offensive . By the end of the war , 1 , 200 had been produced . Comet was fitted with two radio sets : a No . 19 Wireless , for communication with the regiment and the troop , and a No . 38 Wireless for communication with infantry units . Like many British tanks , it also had a telephone handset mounted on the rear so that accompanying infantry could talk to the crew . The 11th Armoured Division was the first formation to receive the new tanks – deliveries commenced in December 1944 – and the only division to be completely refitted by the end of the war . Due to its late arrival in the war in north west Europe , the Comet did not participate in any major battles , although it was used in combat . The Comet was involved in the crossing of the Rhine and the later Berlin Victory Parade in July 1945 . The Comet ' s maximum speed of was greatly exploited on the German Autobahn s . During the following Korean War , the Comet served alongside the heavier Centurion , a successor tank introduced in the closing days of World War II on an experimental basis , but too late to see combat . The Centurion was formally adopted in 1949 and was partly based on the Comet ' s design . The Comet remained in British service until 1958 , when the remaining tanks were sold to foreign governments ; up until the 1980s , it was used by the armies of various nations such as South Africa . Service history . 41 Comet Mk I Model Bs were also used by Finnish Defence Forces armoured brigade until 1970 . The tanks were stored until 2007 , when four of them were auctioned off . Four Comets were delivered to the Irish Army in 1959 and a further four in 1960 . Severe budget cutbacks affected the service lives of the Comets , as not enough spares were purchased . The Comet appealed to the Irish Army as it was cheap to buy and run , had low ground pressure and good anti - tank capability . However , faulty fuses meant the withdrawal of the HE ammunition which limited the tank ' s role to an anti - tank vehicle . With stocks of 77 mm ammunition dwindling in 1969 , the army began an experiment to prolong the life of the vehicle . It involved replacing the turret with an open mounting with the Bofors 90 mm Pv - 1110 recoilless rifle . The project was cancelled due to lack of funds . The last 77 mm Comet shoot was in 1973 and the tanks were withdrawn soon afterwards . One is preserved in the Curragh Camp and two more survive in other barracks . FV4401 . The Comet was used as the basis for the experimental FV4401 Contentious , a self - propelled anti - tank gun mounting a 105mm L7 gun in an open mounting on the shortened hull of a Comet , and using the vehicle ' s hydraulic suspension system to adjust elevation , similar to the method used on the Swedish S - Tank . The vehicle was intended to be air transportable , but the design was cancelled with only one or two built .