It should (hopefully) be fairly uncontroversial that there are underlying legitimate reasons i.e. the fallout from the first decade of Brexit. Unfortunately it seems things are likely to worsen heading into the second decade.

UK economy stopped being dynamic well before Brexit. The simple reality is that the British political class (starting from New Labour and continuing with the current 14 years of Conservative rule) has no vision for Britain beyond the City + M11+ M40, all the infrastructure required to keep that afloat and a managed decline for everything else.

That said of course Brexit only made the above worse.