Though not all these contracts were subsequently filled, and it is not known exactly how many A27's were produced. Leyland Motors were contracted to build 4,256 Centaures, with other companies producing a further 2,000 vehicles. This version was designated the A27L Centaure, and the Meteor powered tank the A27M Cromwell. While the facilities for producing te Meteor engine were being set up, it was decided to continue production of the A27 using the Liberty engine as a temporary measure. Setting up this new engine production line was to take almost a year. The production of the Meteor was passed to the Rover Car Company, which had been tooling to produce the Merlin. Unfortunately Rolls Royce was fully committed producing the Merlin and so was unable tomanufacture the Meteor in any quantity. The successor to the Cavalier the A27 Cromwell, was designed to use this new engine and a pilot model was ready early in 1942. Named the Meteor, this engine developed 600 bhp, more than enough for current needs. In 1941 Rolls Royce produced a de-rated version of their Merline aero engine, used in the Spitfire, Hurricane, and Lancaster aircraft, for tank use. The engine proved adequate in the A13 and Crusader due to their modest weight, but in the Cavalier it was a disaster and the tank was unfit for combat.

Nuffield increased the output to 350 - 410 bhp and this was used to power the A13, A15 Crusader and A24 Cavalier.

As no new tank engines had been developed, most of these tanks were powered by the Nuffield Liberty, an American engine designed in WWI to give an output of 200bhp. The result was that new tanks were rushed into production without proper testing and were to prove unreliable in combat. Many of these were sent to France with the BEF only days before France was defeated, all were abaondoned as their cres were evacuated back to Britain. As a result the British Army had been neglected, so that when war came the Royal Armoured Corps had only a handful of modern tanks in service. It was felt that the large French army would be able to check any German expansion in western Europe should existing treaties be violated. Prior to the outbreak of WWII, Britain relied heavily on military alliance with France.

Wwii centaur tank battle use