Development of the Cavalier initially started as development of the Cromwell tank. In mid-1940, the British were considering which tank should follow on from the new cruiser tanks then being developed. A specification was drawn up by the Directorate of Tanks and Transport which included the 57 mm QF 6 pounder gun. This led to General Staff specification A23 for a cruiser version of the A22 Churchill tank from Vauxhall, and A24 from Nuffield Mechanization & Aero Limited based upon their Crusader tank design. Birmingham Railway Carriage and Wagon Company (BRC&W) also submitted a design based on the Crusader.