There are now more black and Asian pupils in the capital's secondary school system than white children, according to a landmark report.
The study, which is the most definitive study of its kind, found 53 per cent of secondary pupils in London are now from an ethnic background, and warned of 'very high' levels of segregation.
It is the first time that the number of black and Asian children has outstripped white pupils.
There has also been a huge rise in other towns and cities with large ethnic minorities, notably Slough, where non-white children now make up 64 per cent of the numbers, Leicester (58 per cent), Birmingham (52 per cent) and Luton (51 per cent).
Manchester and Bradford are not far behind with 43 per cent.
It comes after David Levin, head of the fee-paying City of London School, claimed pupils are being 'taught in ghettos' as inner-city schools become increasingly divided along racial lines, and warned that London is 'sleepwalking' towards apartheid.
Professor Chris Hamnett of King’s College, who compiled the study, said 'ghettoisation' was too negative a term, but added: 'There are very high levels of ethnic minority segregation in some schools.'
He said: 'London as a whole now has an ethnic minority-dominated secondary school system. In some boroughs, and some schools, ethnic minorities constitute the overwhelming majority of pupils. This has implications for both ethnic segregation in schools, and for pupil attainment.