Cruiser tank The cruiser tank ( also called cavalry tank or fast tank ) was a British tank concept of the inter - war period . This concept was the driving force behind several tank designs which saw action during the Second World War . In British use , the cruiser formed part of a doctrine paired with the " infantry tank " , a much slower but better armoured design intended to work in concert with the infantry in punching holes through enemy lines for the cruisers to exploit . Background . Like the ships of the same name , cruiser tanks were intended to be fast and mobile , and operate independently . In this case , the independence was not from other ships in a fleet , but independence from the slow - moving infantry , their heavier infantry tank s , and artillery . Once gaps had been punched in the enemy front by the infantry tanks , the cruisers were intended to penetrate to the rear , attacking lines of supply and communication in accordance with the theories of J . F . C . Fuller , P . C . S . Hobart , and B . H . Liddell - Hart . The cruiser tank was designed to be used in way similar to cavalry in its heyday and thus speed was a critical factor , and to achieve this the early cruiser designs were lightly armoured and armed . This emphasis on speed unbalanced the British designs ; insufficient attention was paid to armour protection . At the time , the concept of " speed is armor " was considered the overriding concept in the British tank corps ( unsurprising considering its birth in the Landships Committee of the Royal Navy , which also applied the concept to the ill - fated ) . It was not understood at the time that this principle of mobility over all else meshed poorly with the corresponding German policy of trading speed for superior armor and armament , ensuring that even a single round from a German medium tank could easily destroy a cruiser . German infantry were also widely equipped with handheld anti - tank weapons at a rate far exceeding the expectations of the British , further exacerbating the cruiser ' s survivability problems while pursuing breakthroughs against infantry forces . An even bigger problem for most cruiser tanks was the small calibre of their main gun . Most cruisers were armed with the QF two - pounder ( 40 mm ) gun . This gun had adequate armour penetration against early war tanks , but was never issued high explosive ammunition . This made the cruisers highly vulnerable to towed anti - tank gun s . However , as fighting enemy tanks was part of the projected role of the cruiser tanks , they were the first to be upgraded to the heavier 6 pounder ( 57 mm ) gun when it became available , and a great deal of effort was put into developing cruiser tanks armed with the powerful 17 pounder QF ( 76 mm ) gun when it became available . The Cromwell itself had too small a turret ring and it was the following tank design in the British cruiser line the Comet tank with a shortened 17 pdr that entered service late in the war . As the UK had large numbers of US M4 Sherman tanks , the conversion of the Sherman to take a 17 pdr ( as the Sherman Firefly ) proved effective in providing more 17pdr gun tanks . Ironically , despite the emphasis on high mobility , most cruisers were plagued by mechanical unreliability , most noticeably the Crusader tank in the hot and gritty desert of the North Africa Campaign . This problem was usually caused by insufficient development as most of the early cruiser tank designs were ordered " off the drawing board " and was not fully solved until the debut of the Cromwell tank in 1944 , with its powerful , reliable Rolls - Royce Meteor engine . History . In 1936 the British War Office designated two different kinds of tanks for future development : heavily armoured infantry tank s to be used in close co - operation with infantry during attacks , and fast mobile cruiser tanks designed to make forays deep into enemy territory . In 1934 Sir John Carden of Vickers - Armstrong produced new medium tank , the A9 , which was subsequently accepted as an interim design for limited production as the Cruiser Tank Mark I . It was expected to be replaced by a Christie suspension design . In 1937 - 1938 , 125 examples of the A9 were produced . The A9 was lightly armoured but capable of 25 mph and carried a QF 2pdr ( 40mm ) gun that was effective against current tanks . At the same time as the A9 , the A10 , was also designed by Carden for use as an infantry tank . Built on basically the same design but with added armour plate to give 30 mm of protection . It was realised that it was insufficiently armoured for the role . Under " heavy cruiser " designation , it was put into production in July 1938 as another interim design . It had the same armament as the A9 and was the first to be equipped with the Besa machine gun . A total of 175 Mk IIs were produced by September 1940 . Combat experience of the A9 during the Battle of France in 1940 was to reveal several shortcomings , including inadequate armour and a lack of space for the crew , but it nevertheless saw useful service in the Western desert in 1941 . The A10 saw action in France , North Africa and Greece . Orders for the Mk I and Mk II Cruisers were restricted , since the British Army had decided to produce a more advanced and faster cruiser tank which would incorporate the Christie suspension designed by American inventor J . Walter Christie and have better armour . In 1936 , General Martel , a pioneer in tank design who had published works on armoured warfare and pioneered the lightly armoured " tankette " to enhance infantry mobility , became Assistant Director of Mechanization at the War Office . Later that year Martel witnessed demonstrations of Soviet tank designs including the BT tank , which had been influenced by Christie ' s work . He urged the adoption of a tank that would use the suspension system and also follow Christie ' s practice of using a lightweight aircraft engine such as the Liberty Engine or a Napier Lion . The government authorized purchase and licencing of a Christie design via the Nuffield Organization . The tank was very rudimentary and too small for British use , but the suspension was very effective and this became the basis of the Cruiser Mk III ( A13 ) . Following testing of two prototypes , the A13 was ordered into production and a total of 65 were manufactured . The Mk III weighed , had a crew of 4 , a 340 hp engine which gave a top speed of and was armed with a 2 pounder gun and a machine gun . However , when it was introduced into service in 1937 , the Army still lacked a formal tank division . The Cruiser Mk IV ( A13 Mk II ) was a more heavily armoured version of the Mk III . World War II . During early World War II , the Crusader was probably the best - known cruiser , it was first used in mid 1941 and thereafter used in large numbers in the Western Desert Campaign . The contemporary Covenanter was unreliable and was retained in the UK for training use . The Cavalier , Centaur and Cromwell came out of the planned successor to the Covenanter and Crusader . Intended to be in production by 1942 , the project was delayed and the Crusader was upgunned as an interim measure with the Mk . III 6 pounder gun . Cavalier was a development of Crusader . Centaur and Cromwell were an alternative design using the same engine as the Cavalier and the new Rolls - Royce Meteor engine respectively . The Centaur and Cromwell saw action from the Invasion of Normandy onwards . The Comet was a development of the Cromwell using a modified 17 pounder gun and was fielded in the beginning of 1945 . By this point in the war , the firepower and armour protection of the cruisers made them indistinguishable from medium tanks . In the course of the war , technological improvements enabled heavier tanks to approximate the speed of the cruisers and the concept became obsolete . The last of their line was the Centurion . The Centurion was designed to satisfy the " Heavy Cruiser " criterion by combining the mobility of a cruiser tank and armour of an Infantry tank in one chassis . This idea - and the Centurion along with it - then evolved into the " Universal tank " concept , a design that could " do it all " . Ultimately , the Centurion tank transcended its cruiser tank origins and become Britain ' s first modern main battle tank . The cruiser - tank concept was also employed by the Soviet Union in the 1930s , as exemplified by the BT tank series ( , " fast tank " ) .