Desperate to ensure the Spitfire maintained its ongoing combat effectiveness, designers at the Vickers Supermarine Company were almost constantly engaged in modifying, upgrading and improving their famous fighter throughout the Second World War, however, during that time, there were occasions when unexpected Luftwaffe advancements called upon their flexibility and ingenuity. With a significant new variant of the Spitfire at the advanced stages of development, the introduction of a capable new German fighter aircraft in the skies over occupied Europe caused great concern amongst RAF officials, who were now losing Spitfires at an alarming rate and needed an immediate response. With the proposed squadron introduction of the new Spitfire Mk.VIII variant still some months away, Supermarine designers had the idea of mating the intended new powerplant for this aircraft, the Rolls Royce Merlin 60 series engine, with existing Spitfire Mk.V airframes already on the production line, a temporary solution which might just buy them the time they needed.