The Smith Gun was an ad hoc anti-tank artillery piece used by the British Army and Home Guard during the Second World War.
With a German invasion of Great Britain seeming likely after the defeat in the Battle of France, most available weaponry was allocated to the regular British Army, leaving the Home Guard short on supplies, particularly anti-tank weaponry. The Smith Gun was designed by retired Army Major William H. Smith as a makeshift anti-tank weapon, and was put into production in 1941 following a demonstration to the Prime Minister, Winston Churchill.
The weapon consisted of a smooth-bore barrel approximately long mounted on a carriage and capable of firing both modified 3-inch mortar anti-tank and anti-personnel rounds. Despite the promising-sounding nature of the weapon, which at trials in ideal conditions achieved a maximum range of , it was generally regarded as a short-range weapon with an accepted effective range of between . Furthermore, it was heavy and awkward to manhandle, not simply to move around but also to tip over onto the correct wheel on firm level ground so it lay in, and remained in, the correct firing configuration.
It was also alleged to have developed 'a terrifying reputation for killing its crew' when finally issued in 1942, following production difficulties. It was issued mainly to Home Guard units and those units in the regular Army tasked with point defence, such as guarding airfields - and ammunition shortages meant that on average these units only had six or seven modified mortar rounds per gun. Despite these limitations, many Home Guard units developed an attachment to the weapon, some later claiming it was 'one of the best pieces of equipment ever issued to the force'.
Development
With the end of the Battle of France and the evacuation of the British Expeditionary Force from the port of Dunkirk between 26 May and 4 June 1940, a German invasion of Great Britain seemed likely. However, the British Army was not well-equipped to defend the country in such an event; in the weeks after the Dunkirk evacuation it could only field twenty-seven divisions. The Army was particularly short of anti-tank guns, 840 of which had been left behind in France, and only 167 were available in Britain; ammunition was so scarce for the remaining guns that regulations forbade even a single round being used for training purposes.
Given these shortcomings, those modern weapons that were available were allocated to the British Army, and the Home Guard was forced to supplement the meagre amount of outdated anti-tank weapons and ammunition they had with ad hoc weapons, one such being the Smith Gun. The Smith Gun had what Mackenzie describes as an 'unorthodox origin', like many of the other weapons produced for use by the Home Guard. Invented by retired British Army Major William H. Smith, the managing director of Trianco Ltd., a firm of structural engineers. The Smith Gun was intended to be a cheap and easily manufactured anti-tank weapon.
When submitted to the Ordnance Board - which remained unconvinced of its merits - Prime Minister, Winston Churchill, witnessed a demonstration of the weapon in 1941 and ordered that it be put into production.
Design
The Smith Gun consisted of a calibre smooth-bore barrel, in length, and mounted on a carriage 'like a two-wheeled baby carriage', but weighing approximately . A basic shield was provided between the two wheels to cover for the crew but one of the unconventional aspects of the design was when mobile the weapon lay on its side, so that to fire a Smith Gun had to be tipped over onto one of the wheels, which acted as a combined base plate and turntable, while the other proved some overhead protection for the crew. (This meant in firing configuration the Smith Gun resembled a miniature, rather antiquated, naval gun mount of the pre-Dreadnought era.)
This unorthodox deployment gave the Smith Gun 360 degrees of rotation which, combined with a maximum 40-degree elevation, produced a basic firing-plate-mounted field weapon light enough to be towed behind a civilian vehicle, despite not being designed for this. (Home Guard units quickly discovered this fact, having to be prohibited from doing so as it would damage the weapon's wheels (and possibly the axle), inhibiting or even preventing traverse.) Happily, ammunition shortages made the similarly-constructed limber redundant and so a source of spare parts.