Or maybe they're just more forthcoming about it now; but it certainly appears that the Brits were deadly serious about ensuring Airstrip One would remain usable if the Cold War had gone hot: case in point, the vast hidden shelter known as Burlington. H'mm, perhaps it helps motivation if you've actually, you know, had bombs fall?
Update: After more web-browsing, changed title: seems Her Majesty's Gummint promis't civilian nuke shelters. And then never built any. Better/worse than the minimal fallout-only "shelters" in the U.S., mostly located inside the areas that would be wiped out by a nice big USSR nuke? Eh, about the same if needed.
Introduction to Sim
3 months ago