I think the handling of Covid-19 (and there plenty of varied, legitimate criticisms to be made about that) is definitely a UK-specific issue. Not that the mistakes made by the UK weren't also made by other governments, of course.

As for fears for the rest of Europe – I don't doubt that the rest of Europe has problems. My worries are confined to the UK because that's where I live. (To be clear, this isn't me saying I don't care about other countries. But there's only so many problems a person can concern themselves with.) I think the country could very well cease to exist unless we figure a lot of problems out.

The three reasons I listed are the ones that people keep citing. I actually suspect that the UK's problems are longer term and more fundamental. I don't think it's related to either party, either. The Conservative Party of the last few years has not been good for the country, but I'm not convinced Labour will be able to fix our deep, societal problems, either.