Armstrong Whitworth obtained the licence from  the Italian company Ing. Ugo Pavesi to develop and manufacture the Pavesi tractor but passed the licence on to Armstrong Siddeley. This heavy tractor was a machine designed to cross rough terrain, largely with the military in mind. Having four wheel drive and an unsprung centre pivoting two part chassis. Large wheels were usually fitted with solid tyres though innovative soft ground wheels were also experimented with. Pneumatic tyres were fitted to the later reconnaissance version produced at Parkside. No interest was shown in any version by the Mechanical Warfare Experimental Establishment in this country though the Italian Army used them well into the 1940s, these were manufactured by Fiat in their Turin factory.