London's seats vs the Black British population:

Asian British:

White British

It's so interesting to me how ethnicity (and class) plays a major role in vote patterns in London.

London's seats vs most deprived and most wealthy wards:

Wikipedia has good demography maps based on UK census data – most UK big cities have dedicated sites (maps under "Ethnicity"):

London: https://en.m.wikipedia.org/wiki/Demography_of_London

Manchester: https://en.m.wikipedia.org/wiki/Demography_of_Greater_Manchester

Sheffield: https://en.m.wikipedia.org/wiki/Demography_of_Sheffield

Birmingham: https://en.m.wikipedia.org/wiki/Demography_of_Birmingham

Leeds: https://en.m.wikipedia.org/wiki/Demography_of_Leeds

Leicester: https://en.m.wikipedia.org/wiki/Demography_of_Leicester

Luton: https://en.m.wikipedia.org/wiki/Demography_of_Luton

Bradford: https://en.m.wikipedia.org/wiki/Demography_of_Bradford

Nottingham: https://en.m.wikipedia.org/wiki/Demography_of_Nottingham

Slough: https://en.m.wikipedia.org/wiki/Demography_of_Slough

Worth also mentioning here that the constituency (seat) map above is for the House of Commons' 73 London seats, NOT City Hall.