Some London stats. Split (roughly) by former county:
London (Inner/Central): 2,925,548
City of London and boroughs of Camden, Greenwich, Hackney, Hammersmith and Fulham, Islington, Kensington and Chelsea, Lambeth, Lewisham, Southwark, Tower Hamlets, Wandsworth, Westminster
Ethnicity: 60.5% White, 11.1% Asian, 16.4% Black
% with level 4+ qualification: 45.5%
Middlesex (NW): 2,340,391
Barnet, Brent, Ealing, Enfield, Haringey, Harrow, Hillingdon, Hounslow
Ethnicity: 53.3% White, 23.9% Asian, 12% Black
% with level 4+ qualification: 35%
Essex (NE): 1,268,346
Barking and Dagenham, Havering, Newham, Redbridge, Waltham Forest
Ethnicity: 52.1% White, 26.3% Asian, 14.1% Black
% with level 4+ qualification: 24%
Surrey (SW): 1,100,267
Croydon, Kingston upon Thames, Merton, Richmond upon Thames, Sutton
Ethnicity: 69.3% White, 13.1% Asian, 10% Black
% with level 4+ qualification: 38.3%
Kent (SE): 541,389
Bexley, Bromley
Ethnicity: 83.3% White, 4.8% Asian, 7.1% Black
% with level 4+ qualification: 28.3%