As part of the anti-invasion measures following Dunkirk many improvised vehicles were created. One of which was the 4 Inch Mobile Naval Gun. An obsolescent 4″ Naval Gun which was originally designed as secondary armament on large ships as anti-torpedo boat guns. 400 were avainlable and were pressed into service in lots of mounts, one being a Foden DG/6/10 ten ton army lorry. The bodywork was removed and replaced with a basic sheet steel cab with a closable roof to resist the blast of the gun. It could only be fired fore or aft and allegedly one of the commands before firing was ‘Hold onto something’ – they were not ideal platforms but the gun at least was capable going on to become the main armament of many corvettes.