After the failings of the A15 Crusader, a new Cruiser Tank was needed to give British Armoured Units better Mobility and Firepower on the battlefield. A new version of the Rolls Royce Merlin Aircraft Engine was made available for use in vehicles called the Meteor. Rolls Royce was however already stretched producing the Merlin, so production switched to the Rover Car Company for the Meteor. It took Rover some time to gear up to full production of the Meteor but once they became available in quantitiy the newly designed A27M Cromwell Tank was a very fast machine indeed with an ungoverned speed of 40 mph. So fast that it was too much even for the Christie Suspension to handle so production model Cromwells were governed to 32 mph. The new Meteor Engine produced 600 hp which was double that of the old Nuffield Liberty installed in the Crusader. The Cromwell was fitted with a 75mm ROQF gun which was dual purpose, the first British design to have such a feature. The only area where the Cromwell fell down was in Armour Protection which was slightly worse off than the Sherman in the early models but steadily increased in later variants to as much as 102mm. The earlier Cromwells were fitted with Applique Armour which could be fitted in the field to augment it's existing Armour. Although it couldn't match the later German Tanks it was still far more manoeverable and could use it's speed to get out of trouble in most circumstances. The Cromwell first saw battle in Operation Overlord on 6th June 1944 and proved itself a good machine if somewhat under Armoured. But it was to be the Chassis of the Cromwell which was used for the best British Tank design to see service before the war's end the Comet. This was a far superior design to anything that had gone before and gave the British the edge in Tank Design up to the creation of the Centurion. British Cromwell Tanks.