Boulton Paul was one of the two main innovators of gun turret designs for British aircraft, along with Nash & Thompson; they supplied large numbers of installations for British aircraft. Boulton Paul’s designs were largely based on originals licensed from the French company SAMM (Societe d’Application des Machines Motrices), while Nash & Thompson concentrated on the FN designs originated by the firm’s co-founder, Archibald Frazer-Nash. Boulton Paul’s turrets were electro- hydraulic in operation; electric motors located in the turret drove hydraulic pumps that powered hydraulic motors and rams. This was more effective than electric motors alone, and did not require power developed by the aircraft’s engines as did the hydraulic system utilized by the Nash & Thompson design. Production was transferred to Joseph Lucas Ltd.