I doubt any country is overpopulated after a war unless they were immensely overpopulated before their war, or have taken an influx of invaders.
The UK and thus England as a part of there UK is hardly socialist. It is somewhere in the middle with a clear right wing flavour for many decades now. Most of the good social conscience works were brought in ages ago and of late the emphasis has been on taking away power from the "common" people and capitulating to the large global merchants and their friends.
Any country leaving the union would be mistaken at best. The UK is small enough to be considered a single unit without massive compromise yet large enough to gain strength from the unity. This is not a right wing / left wing political issue. It is, or should be, common sense.
It has to be accepted that in a democracy not everyone is going to agree, and there is likely to be occasions where there are different regional viewpoints. But one should accept one can not always have everything one demands and that one has to go along with the majority, not use this discontent as an argument to split into smaller and smaller, and weaker and weaker areas.
That said citizens from each country in the union should be treated equally and whilst there are national tiers of government in all but one, this is an unacceptable situation. Dopey work-arounds are also unacceptable. But seceding from the union is no realistic answer.