In the dark early days of WW2, Britain and Australia both faced the possibility of invasion, Britain from Germany and Australia from the Japanese. Both countries were in desperate need of both men and material, leaving them looking like juicy targets to the rising fascist empires.
In response to the threat, both England and Australia formed Auxilary Units, who were meant to stay behind, and to fight a guerrilla war if that became necessary. Men were recruited and trained, underground bunkers were built, and they were stocked with weapons and explosives to be used against the invaders. These bunkers were hidden from view, usually in wooded areas, and stocked with a variety of weapons, and the best available, which is remarkable with the pressing need for every gun on the front. The men spent the war patrolling their neighborhoods, and learning every rock and hiding place, to be used against the enemy if the time came.
Coleshill House located near Swindon became the headquarters of the Auxiliary Units, and men were trained there before being sent off to defend their little corner of England. Of particular interest to me are the underground bases they built, and there were lots of them, to house 4 or 5 men, Thompson submachine guns, BAR's, Piat anti-tank guns, ammunition, explosives, food and water. The bases were de-activated after the war, but you can still visit one at Coleshill House.
Are there any still out there? These underground bases are still being found, Some police units had thought they were IRA dumps, but were just old Auxiliary unit bases that had never been stood down. For fear of being compromised, the teams were only known to each other and there was no list at Whitehall.
Reading List: A good book on the subject is The Last Ditch: Britain's Resistance Plans Against the Nazis
Google Earth:You can even download a kml file from the Coleshill House website to overlay on Google Earth for the locations of known bases that belonged to Auxiliary Units. A geeky way to enjoy the story.
The following video is a trailer for an available video on the story of the Auxiliary Units.