Based on the Mk V airframe, the HF Mk VI was the first Spitfire specifically intended for high altitude combat, rather than reconnaissance duties. Fitted with a pressurized cockpit and powered by a Merlin 47 of 1415 hp, it had increased span ‘c’ wings of 40 ft. 2 in. Although intended for use in England, No.124 Spdn receiving its first example in February 1941, five were shipped to the Middle East to replace the Special Performance Flight Mk Vs. In the event, the Mk VI’s performance fell short of expectations and only 97 were completed