A "retreat" of white Britons from areas where minorities live is limiting cultural integration, the think-tank Demos has found.
Analysis of the 2011 census figures shows that 45 per cent of ethnic minorities in England and Wales live in areas where less than half the population is white British.
Trevor Phillips, former chairman of the Equalities Commission and Demos associate, said white Britons choosing not to live in minority-dominated areas "ought to make us a little anxious".
The 4.1 million people from ethnic minorities who now live in white minority areas is a significant increase from the 2001 census, when only around one million minority Britons lived in such wards. But integration between ethnic minorities is now more common than it was during the last census in 2001. Demos said that minority white areas were generally multi-minority, since new British minorities such as Somalis had taken up housing left vacant by established minorities, such as Afro-Caribbeans.
Figures also show that more ethnic minorities are moving to live in white-dominated rural parts of the country, with fewer than 800 wards which are more than 98 per cent white compared with more than 5,000 in 2001.
Professor Eric Kaufmann from Birkbeck College, who carried out the analysis, said: "These results present a mixed picture. While ethnic mixing and integration is being helped by more minority people moving into England's whitest areas, the most concentrated minority areas are just becoming more so."