The Guy Armoured Car, or Light Tank (Wheeled) Mk I, was designed in 1938 and was the first armoured car with an all-wielded construction. They were armed with two machine guns in a rotating armoured turret.

Guy Motors lacked the capacity for full-scale production so the design was passed to Rootes who used it as the basis for the Humber. Six Guys were lost in France and the rest served on anti-invasion duties in Britain.