The UK's debate over ethnic segregation should have no limits, the chief of Britain's race watchdog has said.
Trevor Phillips: Controversial views on segregation
Opening a major conference in London, Trevor Phillips said difficult questions on the future of British society were going unanswered.
The build-up to the event's opening was overshadowed by a boycott by London Mayor Ken Livingstone.
Some 900 delegates are attending the two-day event which will hear from 160 speakers from around the world.
Mr Phillips said that the Commission for Racial Equality's convention would look back on 30 years of race relations action - but also bring into sharp focus critical problems building up today.
Mr Phillips, soon to head a new equalities super-watchdog, said the challenges included fears of growing ethnic segregation and isolation in some inner cities - and little contact between white people and those of other backgrounds.
"If we truly want to create a nation at ease with its diversity, are we facing up to the challenges of the future?" he said. "How do we cope with the rising frictions between people of difference races and faiths?"
Mr Phillips repeated and defended his controversial warnings following the 2005 London suicide bombings that the UK was experiencing rising segregation.
"As a nation we are becoming more ethnically segregated by residence - and inequality is being amplified by our separate lives. It is true that some areas are more integrated, but only in the sense that one black person joining an all-white tennis club integrates it.
"The real crisis lies in the areas which the middle-class minorities are leaving behind - areas which are becoming more and more ethnically concentrated and exclusive."
Mr Phillips said his warning was not made to grab headlines - but to alert people that those likely to lose out most were the very minorities stuck in these communities.
"If we want to change Britain then all of Britain must be part of the debate and part of the solution," he said.
"And that means that people of all races, all colours, all faiths and all stations in life have a role to play. This is what we mean by moving race from the margins to the mainstream - moving from protest to real politics."
The event is being boycotted by London Mayor Ken Livingstone.
Mr Livingstone, who has clashed frequently with Mr Phillips, had been expected to attend as mayor of one of the most ethnically diverse cities in the world.
But in a letter to the CRE chief, Mr Livingstone said Mr Phillips was using inflammatory language and alarming headlines which would damage community relations.
One conference session entitled 'Rivers Of Blood: did Enoch Powell get it right?' was dropped before the event opened.
The CRE said it was disappointed by the snub and said that the mayor's criticism was part of a sustained campaign against the commission.
Ken Livingstone: Refusing to attend major event
Ruth Kelly, the Communities and Local Government Secretary, opened the conference saying ministers were now asking whether too much attention had been given to individual minorities rather than to projects to build unity in society.
"We may have been too ready in the past to focus on separate provision - and not ready enough to ask how to get people to come together," said Ms Kelly.
"It is not cultural diversity itself which is being questioned. The issue is one of balance between preserving a distinctive identity and closer integration.
"We must respect difference but this must not been at the expense of having a society and local communities without a common purpose."