The Spitfire Mk. VIII was to going to use the larger Merlin engines so the airframe of the earlier Mk. V had to be redesigned. This kept the new mark from entering service until June 1943. The Mk. VIII was produced in 3 versions; the standard fighter F.VIII with the 1,560 hp Merlin 61; the high-altitude fighter HF.VIII with the 1,655hp Merlin 70 and the low altitude fighter LF.VIII with the 1,705 hp Merlin 66. The Mk. VIII was going to be the answer to the Fw-190.

The leading RAAF ace in the Western Deserts of North Africa was Clive “Killer” Caldwell who racked up 20.5 kills. When the RAAF squadrons were recalled for homeland protection Caldwell was given command of the Darwin Wing where he scored 7 more victories against Japanese aircraft. In November 1943 the RAAF started to receive 251 former RAF Mk. VIIIs. Caldwell flew 3 Spitfire Mk. VIIIs one of which was former RAF JG543. Caldwell was the highest scoring Spitfire pilot and Australian pilot in the SWPA (South West Pacific Area).