Those two had to be the DUMBEST two people in the UK!

By UK standards they're above average.

The book was based on the civil defense advice of the time. Now it makes as much sense as the 'duck and cover' drills they taught American school kids.

At best, I'd say this old couple were incredibly naive and old-fashioned, thinking that nuclear war would be like their nostalgic view of WW2 and that they'd be able to relive that "wartime spirit" they so enjoyed back then. The woefully-inadequate "Protect and Survive" UK Government booklet didn't help matters.

Ironically, the old man's son knows better when he calls him by phone before the nuke hits: the son is singing about death and futility and the father is angry with him for being so defeatist. Well, old man, nuclear war is not worth surviving, it's a horror show beyond belief according to estimates and survivors of Japan's nuke strikes. If nuclear war was inevitable now, I'd go towards a primary target and hope it took me out quickly.

They were naive, but I don't consider them dumb.