From the end of the Second World War to its quiet abandonment in 1968 Britain operated a policy of civil defence, which sought to plan for both continuity of government and the survival of the British public in the event of a nuclear strike.
A new book by Matthew Grant (reviewed in depth here by Jennifer Cole of the Royal United Services Institute) shows how a combination of anti-nuclear campaigns and economic realities effectively forced government to admit that any affordable preparations would make no effective difference in the face of atomic attack.
Thus post-nuclear holocaust scenarios (even those produced by government) became increasingly fatalistic, and the idea of post-apocaplyptic survival increasingly unlikely, the pathos of which being brilliantly captured by Raymond Briggs in his seminal When the Wind Blows.