Is Population increase in your area possible?

[Devonian]

Exactly, but that still doesn't mean that the areas will have sufficient water; sewerage and power supplies if a significant proportion of the population is for example moved out of Birmingham or London, then the additional strains it would place on the infrastructure in other areas could result in a bigger disaster than staying put.

Image being shipped out from Birmingham to Somerset and then having nowhere to go; no food; and then the power and water goes off. 30,000 refugees in say Taunton would not be happy, and that is when the riots would happen, whereas if they were left where they were, then I think a lot of people would still cope, particularly in a time of adversity. It may mean going out collecting water from standpipes/bowsers etc, but people would be more willing to accept that I feel.

Basically, I struggle to see anything that would result in a mass evacuation as seen in the 1940's, other than following something like a nuclear explosion.