I just watched a documentary about a hypothetical German occupation of the UK and the British plans to respond to it.

I also recently finished the Sabbat Worlds short stories and the Gaunt's Ghosts books set on Gereon which deal with pro-Imperial partisans. The model in the Black Library seems to be the French Maquis or the Soviet-aligned partisans in Eastern Europe and Russia.

However, the documentary entitled "Hitler's Britain" (available to watch for free on Hulu) talks about another approach to resistance in the form of the British Auxiliary Forces. The BAF were organized by HM Government in 1940 to function as pro-British partisans in the event of a successful German invasion of the UK.

If an Imperial world was faced with imminent invasion by xenos or chaos forces, might not the local government organize a resistance movement in situ to resist the occupation?

In the case of the British, the local chief constables vetted and recruited young men and women of exceptional ability, specialized skill sets (like demolitions, locksmithing, gunsmithing, etc.) and/or loyalty to the crown. These recruits were then trained by the British Army in unconventional warfare and commando operations. They were provided with weapons, specially constructed underground OPs (operations posts) were built by the Royal Engineers and were stocked with provisions and communications gear. Other operatives were recruited within the Church of England, the Freemasons, the BBC and other bodies to provide points of contact between cells and between the resistance as a whole and the British Army.

This was all the brainchild of one Major-General Sir Colin McVean Gubbins KCMG, DSO, MC who commanded the Special Operations Executive, which had helped start and supply most of the pro-Western partisans on the Continent. He envisioned the BAF as going to ground when the Germans arrived and to remain inactive until ordered to become operational by the British Army or in the event of British surrender to assist an American/Commonwealth counter-invasion of Britain. The BAF would harass the German army of occupation, blow up airfields, train lines, assassinate German officials and British collaborators and generally make life hard for the Germans. Among their targets were some that sound ironic but would fit the 40k meme perfectly - they were. for example, to kill the local chief constable who recruited them since only he knew the names of all the resistance fighters, his silence was too vital to risk by letting him live.

Okay, so to bring this to 40k, a world is threatened with invasion - to prepare for the worst, the Imperial authorities have local Arbites commanders identify and recruit citizens with certain skills and vet them for political reliability and loyalty to the Throne. These 'special action groups' are organized in a cellular fashion with contact between cells maintained by a network of go-betweens recruited from a variety of business and social organizations with few obvious ties to the Administratum. Other go-betweens to liaison with the Imperial Guard are recruited from the Ecclesiarchy and Guild organizations. Cells are trained by the Guard to function as irregulars operating behind enemy lines.

Any thoughts on this as a viable army background?