As it is in 2012, about 14% of Britons are not ethnically British and about 8% of Britons are neither ethnically British or white. For a European country, the United Kingdom has had a notable amount of immigration.
What's the highest percentage of non-white, or at least non-European, people that Britain can have by the 21st century?
Bonus points if the increased amount of immigrants doesn't mean a different accent than the ethnically British Britons. Yeah, I know there are hundreds of British accents.