ZADIE SMITH, a novelist born to a black Jamaican mother and a white British father, recently recalled that when she was growing up in Willesden Green, a London district with a large immigrant population, “nothing could be more normal than a mixed-race girl”. The surprise, she said, was entering publishing and finding that people thought it unusual. Nobody could get that impression now: Britons are mixing at extraordinary speed.

The 2011 census revealed a country that is decreasingly white and British: England’s ethnic-minority population grew from 9% of the total in 2001 to 14%. But the biggest single increase was in the number of people claiming a mixed-ethnic background. This almost doubled, to around 1.2m. Among children under the age of five, 6% had a mixed background—more than belonged to any other minority group (see chart). Mixed-race children are now about as common in Britain as in America—a country with many more non-whites and a longer history of mass immigration.

As Britain’s mixed-race population swells, another group appears destined to shrink. The Labour Force Survey reveals that 48% of black Caribbean men and 34% of black Caribbean women in couples are with partners of a different ethnic group—with higher proportions still among younger cohorts. Black Caribbean children under ten years old are outnumbered two-to-one by children who are a mixture of white and black Caribbean.

Rob Ford of Manchester University points out that Caribbean folk are following an Irish pattern of integration, in that their partners are often working-class. The Irish parallel also suggests they will eventually be fully absorbed into the British population. Polls show that adults who are a mixture of white and black Caribbean tend to see themselves not so much as black, Caribbean or even as British, but rather as English—the identity of the comfortably assimilated.

Indians, who began arriving in large numbers in the 1960s, were slower to mix. They are now doing so—but along Jewish, rather than Irish, lines. For them, assimilation follows education: according to research by Raya Muttarak and Anthony Heath, Indians with degrees are far more likely to marry whites. Indians are not so much marrying into the white majority as into its suburban middle class, says Shamit Saggar at the University of Essex.

Their children are quietly transforming Britain’s suburbs and commuter towns. Whereas Asians are still concentrated in cities such as Leicester and in London boroughs like Tower Hamlets and Harrow, mixed Asian and white children are widespread (see maps). In Chiltern, an affluent commuter district in Buckinghamshire, 5% of children under five years old were mixed Asian and white in 2011—more than in most of London. Their parents may have met at university or while working in the capital. Within Birmingham, too, mixed Asian and white children are especially common in the largely middle-class white suburbs of Edgbaston, Moseley and Harborne.

Still warming up

Pakistanis and Bangladeshis mostly remain in cities, and are mixing more slowly. Just 8% of Pakistani men and 7% of Bangladeshi men in couples are with people of a different ethnic group, and the proportions for women are smaller. Oddly, older Pakistani men are more likely to have partners of another ethnicity, perhaps because many early migrants were single men. But even these groups are assimilating: another study finds that Pakistanis and Bangladeshis born in Britain are far likelier to socialise with whites than their parents were.

Britain’s newer minorities are blending into the larger population, too, but in ways that defy easy categorisation. Mixed black- African and white children are particularly common in working-class suburbs and commuter towns such as Croydon and Southend-on-Sea, possibly because black Africans are rarely tied to city centres through social-housing tenancies. They are also mixing with new immigrants from continental Europe. Most of the 21,000 children born to Polish mothers in 2012 had Polish fathers; but of the rest, 23% had African or Asian fathers.

Such esoteric partnerships can confuse the authorities. Last November the Home Office invited journalists to accompany officers on a raid of an apparent sham wedding between an Italian man and a Chinese woman in north London. After interrogating the bride, groom and guests, the officers emerged sheepishly to admit that the union was probably real.

As race becomes less clear-cut, schools, hospitals and police forces, which record people’s ethnic identity at almost every opportunity, will have to deal with more fragmented definitions. So too will researchers trying to measure racial injustices. Confusingly, police officers now record the ethnicity of the people they stop and search according to two separate systems: observed ethnic appearance (which does not include a mixed-race category) and self-identified ethnicity (which does).

Politicians in the habit of treating Britain’s ethnic groups as distinct “communities” will also have to adapt. The shrewder black and Asian politicians have already built power bases that do not depend on ethnic block votes (see Bagehot). Speeches such as the one made by Tony Blair in 2007 about the culture of black youth violence will look silly when so many black teenagers have white parents too. Crude racist politics, thankfully now rare in Britain, ought to become almost impossible as more white families acquire non-white members. Englishness, which has remained distinctly a white identity for many, may become less exclusive.

Most of all, the rise of mixed-race Britain shows that Britain is capable of absorbing even large numbers of newcomers. For the young, who are used to having people of all backgrounds in their midst, race already matters far less than it did for their parents. In a generation or two more of the melting pot, it may not matter at all.