If you want to consider prototypes as programs then the British could add the Gloster F5/34, the Bristol 146 and the Martin Baker MB 2. Any others?
As a matter of pedantry, these were all built to the one specification: F.5/34 was a fighter spec to which the Gloster, the Bristol 146 and the MB.2 were all built. No production model was chosen. Six firms were sent tenders, to which three prototypes were built.