The A13 Cruiser was developed into the A15 Crusader then the A27 Cromwell. The use of the powerful Rolls Royce Meteor engine, derived from the Rolls Royce Merlin, gave the Cromwell high speed and mobility. The final British cruiser design to see service was the A34 Comet; a development of the Cromwell, it carried a high velocity 77 mm gun derived from the Ordnance QF 17-pounder anti-tank gun; one of the most effective Allied anti-tank guns of the war, although the Comet itself saw very little combat.