A closer look at the Home Guard 'heavy' weapons-
The Spigot Mortar (aka Blacker Bombard) was the forerunner of the PIAT but 10 times bigger and heavier; it fired a finned AT-bomb out to an effective range of 100 metres, or an HE finned bomb to 500m.
A number were also issued to the Regular Army and destroyed at least one German tank at Tobruk, but it was cumbersome when mounted on legs, and immobile when mounted on a fixed base and was later phased out when the smaller lighter PIAT was introduced.