Cornwall
Fragment of a discussion from User talk:Rua
Yes, that's why I removed Greater Manchester from the United Kingdom category, because they are a subdivision of England specifically and not of the UK.
That hasn't made Cornwall appear in the England category, and Greater Manchester is still there.
I no longer see Category:en:Greater Manchester in Category:en:United Kingdom after doing a null edit on the former.
All three (Cornwall, London, Greater Manchester) are appearing in Category:en:England now.