The development of the design by Sir John Carden at Vickers-Armstrongs Ltd began in 1935. The General Staff specification required a cheap tank, requiring the use of already commercially available components. It resulted in a small two-man vehicle with a low hull and a small cast turret. The turret was fitted with a single heavy machine gun, either a .303 Vickers machine gun or a larger, Vickers .50 machine gun. Designed for quick delivery as well as low cost, the A11 used many stock parts from other vehicles: a Ford V8 engine, a Fordson gearbox, a steering mechanism similar to the one used in Vickers light tanks and suspension adapted from the Mk IV Dragon artillery tractor, that was based on the Vickers 6-Ton Tank Model E.