Yes, as UVS & Rpley say, the Charioteer was based on the Cromwell chassis - a panicked answer to the percieved superiority of Soviet heavy armour circa 1950 - until adequate numbers of Centurions were produced, at which point we sold them off to (as seen in Old Guards photos) Finland, Jordan and Egypt being other recipients.
Perhaps the 'worst tank' label is a little unfair for a stop-gap design, though undoubtedly the turret was a fugly compromise, tall and fairly thinly armoured in order to fit the large 20 pdr. Arguably the design is no worse than either the Firefly or Challenger - all three had the problem of their muzzle flashes being so large that the gunner & TC were effectively blinded - the flare in the round's base not lasting as long as the effects of the flash and smoke on the gunner. Consequently the TC would often stand off to one side to observe the fall of shot. But of course all of these vehicles were temporary compromise solutions to a problem and should be judged as such, the Charioteer's designers not being aware at that point of the myriad flaws in the ISIII which had so terrified the allies at the Berlin victory parade in 1945.
