BBC newsreader George Alagiah has warned that multi-culturalism in Britain has created segregated areas like "apartheid's social engineers dreamed of".
He said "a combustible combination" of segregation and deprivation may be fuelling home-grown terrorism.
The Sri Lankan-born broadcaster made his assessment in his book, In A Home from Home.
He likens the present situation to "a garden that has been allowed to run wild".
Mr Alagiah adds: "I'm convinced the answer lies not in getting rid of multiculturalism altogether, still less in trying to end the diverse flow of people to Britain, but in trying to resurrect its original goal - the mixing of people of different races on an equal footing."
His own education at a private school in Southsea, Hampshire, taught him "how to become British" but many Asian-schools were "de facto faith schools", he said.
Mr Alagiah said segregation in schools was mirrored in wider communities such as Bradford, where, he said, the city's ring road was like a boundary - "the inner neighbourhoods are almost entirely peopled by Asians, while the whites live outside".
The distinct division of a city along ethnic and racial lines, a generation after legislation was introduced to achieve the opposite, was staggering, he wrote.
He said similar segregation existed in Halifax, Luton, Southall, Leicester and many other areas.
Referring to the July 7 London bombers, he argued whether Britain had "set any standard, demanded any sort of behaviour, offered any form of encouragement that might have enticed them away from savage influences".