Blacker Bombard The Blacker Bombard , also known as the 29mm Spigot Mortar , was an infantry anti - tank weapon devised by Lieutenant - Colonel Stewart Blacker in the early years of the Second World War . Intended as a means to equip Home Guard units with an anti - tank weapon , at a time of grave shortage of weapons , in the case of German invasion , it was only accepted after the intervention of Churchill . Although there were doubts about the effectiveness of the Bombard , many were issued though few , if any , saw combat . 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were available were allocated to the British Army , and the Home Guard was forced to supplement the meagre amount of outdated weapons and ammunition they had with " ad hoc " weapons . One of these was the Blacker Bombard , designed by Lieutenant Colonel Stewart Blacker , the origins of which went back to the 1930s . During the early part of the 1930s , Blacker became interested in the concept of the spigot mortar . Unlike conventional mortars the spigot mortar did not possess a barrel , and instead there was a steel rod known as a ' spigot ' fixed to a baseplate ; the bomb itself had a propellant charge inside its tail . When the mortar was to be fired , the bomb was pushed down onto the spigot , which exploded the propellant charge and blew the bomb into the air . Blacker began to experiment with the concept in the hopes of creating a platoon mortar that was lighter in weight than the one used by the British Army at the time . This evolved into the Arbalest , which he submitted to the Army but was rejected for a Spanish design . Undeterred by this rejection , Blacker went back to the design and came up with the idea of an anti - tank weapon , although he was initially stymied in his attempts to design one because the spigot design failed to generate the required velocity to penetrate armour . However he was eventually successful in creating an anti - tank mortar , which he named the Blacker Bombard . When the Second World War began , Blacker was a lieutenant - colonel in the Territorial Army . He had offered his Bombard to the War Office for two years without success but was introduced to the government department of Military Intelligence Research ( MIRc ) later known as MD1 , which had been given the task of developing and delivering weapons for use by guerilla and resistance groups in Occupied Europe . Blacker showed his list of ideas to the head of MD1 , Major Millis Jefferis , who was taken with the design for the Bombard . He argued that it could serve in an anti - tank and artillery capability , and claimed that it would have similar anti - tank properties to the 2 pounder anti - tank gun coupled with approximately the same range as the 3 inch mortar . Objections were raised by the Director of Artillery and other government officials , but on 18 August 1940 the Prime Minister , Winston Churchill , attended a demonstration of the weapon . Churchill took a liking to the weapon and ordered it into full production . It would act as a temporary anti - tank weapon for the Home Guard until more 2 pounders could be supplied to them . It was decided by General Headquarters Home Forces that Bombards would be useful as an anti - tank weapon for use by regular forces , as well as the Home Guard . General Alan Brooke entertained doubts about the weapon ' s effectiveness , but believed that its simplicity would allow it to be used by younger soldiers . In Southern Command , 14 , 000 were ordered for use by forces in that area ; twenty - four were to be issued to anti - tank regiments , twelve to troops assigned to guard aerodromes , eight per brigade and two for each Home Guard company . However , RAF personnel were forbidden from using the weapons , a restriction which was extended to the RAF Regiment when it was formed in 1942 . Design . The Bombard was a 29mm spigot mortar , weighing between 112 and 360 lb , placed on top of a swivel or pivot . It was able to fire a 20 lb high - explosive bomb to a range of approximately 100 yards ; when the bomb detonated , it was able to inflict significant damage on a tank , although it was unlikely to actually pierce the vehicle ' s armour as the projectile was not able to gain sufficient velocity . It was served by a crew of between three and five men The Bombard was considered to be most effective at short range , with targets being engaged with ' considerable success ' at a range of between 75 – 100 yards . It was a muzzle - loaded weapon and therefore had a slow rate of fire , averaging between six and twelve rounds per minute ; as such it was considered vital that the weapon be well - camouflaged and that it hit the target with the first shot . Two types of ammunition were provided for the weapon – a 20 lb anti - tank bomb and a lighter 14 lb anti - personnel bomb , with each weapon being issued with 150 rounds of the former and 100 of the latter . The anti - tank rounds were found to possess several problems . They had insensitive fuze s , which meant that they would often pass through an unarmoured target without detonating , and when they did explode fragments were often thrown back at the crew . The Bombard was either affixed to a large cruciform platform , or an immobile concrete pedestal ; in either case would usually be placed in range of defensive positions , such as road - blocks . It seems that there was a preference for the Bombard to be used primarily in a static role , with extra mountings being built by the Royal Engineers to provide alternative positions from which the weapon could be fired . In a static position , the weapon was usually emplaced in a pit with ammunition lockers nearby . Operational history . The first Bombards appeared in late 1941 , and were issued to both regular and Home Guard units ; in Southern Command , no more were issued after July 1942 . By that time , approximately 22 , 000 of the Bombards had been produced and issued to forces throughout the country . By November 1941 , concerns were already being aired about the suitability of the weapon and it was unpopular with a number of units ; some attempted to trade their Bombards for Thompson submachine gun s or refused to use them at all . However , Mackenzie cites the argument of the historian of the Ministry of Food Home Guard battalion , who stated that the issuing of the Bombard meant that the Home Guard was being taken seriously by the government . Mackenzie also argues that the Bombard did have a positive side , as it equipped otherwise unarmed Home Guard personnel with a weapon , and was a ' public relations ' success . It would appear that a number of Bombards saw action with the British Army , being used in an anti - personnel role in the Western Desert Campaign , although their use may have been limited due to their weight . The design of the Bombards was the basis for the Royal Navy , anti - submarine weapon known as the Hedgehog . Large numbers of fixed , concrete pedestals for Bombards were installed and a significant number survive in their original positions in many parts of the United Kingdom . The " Defence of Britain Project " , a late - 1990 ' s field survey of 20th century military landscape features by the Council for British Archaeology , recorded a total of 351 surviving pedestals . Users . Some of the users of the Blacker Bombard included :