Unbeknownst to most people, the UK was one of the first countries to have an organized, armed resistance movement to fight the Nazis in WWII. They were known as Auxiliary Units , headquartered at Coleshill House. They were groups of civilians detailed to stay behind and carry on the fight even if Britain were invaded and overrun and the government forced to flee to Canada.
Information about them was very hard to find in the pre-Internet era, because very few records were kept — they didn’t want the Germans to find out about them. Now, of course, they have their own Wikipedia page. In some cases they masqueraded as Home Guard units, in others they were just groups of people who were given special training. They kept stocks of weapons and explosives, and were prepared to conduct sabotage operations against German units and infrastructure. Since in some ways they didn’t officially exist, there was no way for them to disband, and their sleeper cells lay dormant for decades after the war.
When we lived in England, in the early ’70’s, there would periodically be a news item about a former AU member contacting the army or police and saying “I am 90 years old now, and can no longer do proper maintenence on the 100 kilos of explosives and the collection of automatic weapons that have spent the last thirty years buried under my garden shed. What should I do with them?” Just another example of how people from that time felt they had a pact between themselves and the government, and were willing to keep secrets very nearly unto death. More recently, of course, government have violated those pacts, and squandered that good will.
Recently, archaeologists have started surveys at the AU headquarters at Coleshill House to see if they could uncover any physical evidence.
Updated to include mention and link to the Wikipedia entry.