The possibility that the RAF would run short of fighters during the Battle of Britain prompted adaptation of the 750hp Rolls-Royce Kestrel 30-engined M.9 tandem two-seat advanced trainer as an emergency single-seat . The rear seat was removed, together with part of the rear cockpit glazing, a gunsight was installed and six 7.7mm machine guns were mounted in the wings. Assigned the designation M.24 retrospectively, a total of 23 fighter conversions was produced, but, in the event, no need arose for their operational use.