I don't think that they are hillbillies with KKK leanings, but they don't need to be. There are absolutely some post-industrial places where the name Thatcher is an epithet that will never vote Tory, but there are a lot of erstwhile Labour strongholds that just aren't voting Labour for a generation or more. Beyond that, look at the demographics in 2019:
https://www.ipsos.com/en-uk/how-britain-voted-2019-election
- There was a sizable swing toward the Conservatives among people without degrees. As there has been in the US.
- The Conservatives won against Labour among white voters by 19%, and lost with identified minorities by 40%.
- A sizable gender gap is opening up, particularly with younger demos, with women more likely to favour Labour or the Lib Dems, and men more likely to vote Conservative.
And here we see that reinforced: big gains for Labour in London, while many former Labour strongholds form a Conservative breakwater.
Those aren't just trends in the US and the UK. It's also the trend in Canada, and most of Europe, as well. Conservative parties are increasingly the domain of reactionary populism, and reactionary populism is increasingly the preferred political flavour of the white working class.