Valiant tank The Tank , Infantry , Valiant ( A38 ) was a British tank design of the Second World War that only reached the prototype stage . Intended to meet the specification for a lightweight but heavily armoured tank for use in the war in the Far East , it proved to be an ergonomic failure . The sole example was retained by the School of Tank Technology after the war as a lesson to its students . Design and development . The Valiant , under General Staff specification A38 , began as a candidate for an assault tank , with the thickest armour on the lowest possible weight , for use in the Far East . It was to be similar in intention to the 40 - ton A33 Excelsior although far lighter . As the Valiant managed the same 114mm frontal armour with only 27 tons , it managed to achieve its primary goal , but only by making unacceptable compromises elsewhere . At a time when British tank design was already at its nadir , this " terrible price for the weight concession " led to what is probably the worst British tank of the war . The design brief of December 1943 called for three prototypes of a small , heavily armoured tank for the Far East . Speed across open country was less important , as was performance against armour . Design work started with Vickers , but they soon passed it to Birmingham Railway Carriage & Wagon , then finally Ruston & Hornsby , who built the single boilerplate prototype in 1944 . Vickers ' original intention may have been to use parts of their Valentine infantry tank where possible , but this did not survive the production choices of the other manufacturers , nor was the running gear of the far lighter Valentine compatible with the needs of such heavy armour . The largest point of commonality was the choice of engine , the 210 bhp General Motors 6004 two - stroke diesel , as used in later marks of Valentine . Construction was like that of the Matilda infantry tank - large cast armour pieces bolted together . Suspension was by six equally sized wheels on each side , with independent wishbone suspension units for each , rather than bogies . Concern was expressed about the possible fragility of these units in combat , but Valiant was never taken seriously off - road to test them . The drivetrain was to the rear , from a 210 bhp diesel . This low power limited the tank to a predicted top speed of 12 mph , although this was still acceptable to both the infantry tank and " assault tank " concepts . Following from the later Valentine VIII & XI models , the turret was to accept either the QF 6 pdr or the QF 75 mm , with space for a turret crew of three ( commander , gunner , loader ) . This was achieved at the cost of a large heavy turret with near - vertical faces and a massive cast front face with distinctively prominent bolts . The mantlet was internal and a weak point against accurate fire at close range . Unlike the late model Valentines it had a co - axial machine - gun . The Valiant ' s suspension was tested by the Fighting Vehicle Proving Establishment at Chertsey in May 1945 . The first day gave minor problems and was abandoned after only of easy on - road driving . However , the driver was already exhausted by this time , finding that the steering levers needed his full weight to operate and that the seat , footbrake and gearlever all carried risk of physical injury in using them . The Officer in Charge decided to abandon the trials there and then as it was impossible and unsafe to continue , reporting that " in his view the entire project should be closed " There were also issues with weight distribution and the ground clearance of only 9 inches , and by that point of the war there was no longer a need for the tank . The Valiant project was terminated . Variants . A Valiant II was mentioned in late 1943 , but little more was heard of it . In February 1944 there was more detailed discussion of a Heavy Valiant , which may have been the same and has been reported as such in some sources . The Heavy Valiant was a substantially different vehicle , only using the turret and driver ' s compartment of the Valiant on a hull derived from the A33 Excelsior and its T1 suspension . This gave armour of 9 ( hull front ) and 10 inches ( turret ) thickness . Weight was now estimated at 42 tons , which is comparable with the original Excelsior despite almost doubling the armour thickness , and so this must have been a much smaller tank . Power was doubled to cope with the weight , using the new and compact 400 bhp Rolls Royce Meteorite engine ( a cut - down V8 Meteor ) and an improved transmission . The mistake of the Valentine was to be repeated , where the turret was up - gunned to the 95mm howitzer of the Centaur IV at the cost of forcing the commander to take over the loader ' s task in a two - man turret . There is a record of a prototype having gone to the ranges at Lulworth Cove for trials in January 1945 , but no other record of what it looked like . Present day . The sole Valiant was retained by the School of Tank Technology , where students were treated to an inspection of it at the end of their course and invited to find fault . David Fletcher wrote of this : " One hopes they started early in the morning . " The Valiant can now be seen at The Tank Museum .