Did British aircraft factories use prototypes for air defense during the Second World War?
Short answerGenerally no; operational RAF fighters based nearby or on the same field provided factory defense.
NotesA viewer asks whether British factories used prototype fighters for local defense as German factories sometimes did. They generally did not need to. RAF fighter units were based nearby or even on the production airfield to provide protection. The broader air-defense aim was to keep hostile aircraft as far from the factories as possible rather than improvise with development machines.