It’s important to understand that “middle class” has a very different meaning in the UK than the US. In the UK “middle class” generally means “posh”, you could see it as a shorthand for “upper middle class”.
I think it's probably very contextual. For example, The Telegraph reported that 'Seven out of 10 people view themselves as [middle class]'[0].
That's probably a result both of lower wage people feeling aspirational (and associating "working class" with manual labour) and many people with traditionally upper class traits feeling embarrassed to publicly suggest they are superior.
As the BBC notes, 'David Cameron - educated at Eton - has described himself and his wife - the daughter of a baronet - as part of the "sharp-elbowed middle classes".'[1]
I think it's probably very contextual. For example, The Telegraph reported that 'Seven out of 10 people view themselves as [middle class]'[0].
That's probably a result both of lower wage people feeling aspirational (and associating "working class" with manual labour) and many people with traditionally upper class traits feeling embarrassed to publicly suggest they are superior.
As the BBC notes, 'David Cameron - educated at Eton - has described himself and his wife - the daughter of a baronet - as part of the "sharp-elbowed middle classes".'[1]
[0] https://www.telegraph.co.uk/finance/personalfinance/8393834/...
[1] https://www.bbc.co.uk/news/magazine-25744526