The culmination of British efforts was the Comet tank with a cut down 17-pounder design, the 77 mm HV. The Comet was a further development of the Cromwell, a "heavy" cruiser tank, which sought to remove the need for 17-pdr armoured vehicles, such as the Challenger or Firefly in tank platoons. The Comet reduced its road speed in comparison to the Cromwell to , in favour of better armour protection and a weapon able to penetrate the armour of the heavier German tanks whilst not sacrificing HE capability. The tank had a short service life as design for the Centurion was already well underway, with the first prototype arriving in 1945.