The Smith Gun was invented by the chief engineer of the Trianco Engineering
Company. It was developed as a private venture in 1940 and offered to the
British Army as an emergency gun for issue to the Home Guard. At first the gun
was refused by the Ordnance Board but it appears to have got into Home Guard
service by some back-door route and was on issue by June 1941.
The Smith Gun is probably one of the most unusual 'artillery pieces' ever to have been produced. For an 'emergency issue' gun it is, in places, as over designed and over engineered as it could be. Yet despite this certain concepts of this gun should go in the 'why didn't we think of this earlier' group.
The firing lever and cable appear to have been borrowed from a motorcycle brake/clutch lever and cable. The gun and limber/ammunition trailer could be towed behind an ordinary car, the gun was simply turned over onto one of its wheels to become ready for action. The gun could also be used without the limber which just held additional ammunition for the weapon.