With immigration a big topic in the European and local elections, BBC News local government correspondent Mike Sergeant visits a school in north-west London, where there are 42 languages spoken in the playground.
Byron Court in Brent is one of the most diverse schools in the UK.
The playground at lunchtime is an extraordinary mix of vibrant London life.
Children from Iraq, the Philippines, Somalia, India, Nepal, Cyprus, Romania and Slovakia, to name but a few, mingle happily and play together.
One of the most striking things is the almost total absence of children from families that might describe themselves as "white British".
This is not particularly unusual for a primary school in parts of London and some other big cities.
As immigration has become a more central political issue in recent years, so the questions have intensified about the effect of such pronounced diversity on the educational achievement of pupils from all backgrounds.
"Keeping unity at school is very important", said Martine Clark, the school's executive head teacher.
"It's vital there's no differentiation between any languages or any culture. We do that by celebrating the diversity of the culture in the school."
She says the children that come here are adaptable and resilient. Having such a rich variety of backgrounds actually makes the pupils better learners, she believes.
Byron Court says adequate funding and enough outstanding teachers are vital to integrating children whose families are often scattered across the globe
Some of the children told me they struggled at first, often not understanding simple instructions in the classroom or the playground, but most said they were comfortable in the school after a few months.
After several years, many have turned the disadvantage of not speaking English into the advantage of being fully bilingual.
Martyn Pendergast, an education officer with Brent Council, said: "Inevitably there is some impact - particularly at the earlier end of primary school.
"It takes time to learn a new language.
"But children learn very quickly. By the time they're 11 they've caught up with national standards and by the time they're 16 they're flying".
Some experts have, however, voiced worries that in other schools those who don't speak English at home aren't getting the level of support they need.
The outcomes that these children can expect, though, vary hugely.
Those who don't speak English but come from a disciplined background and a high level of learning in their original language often progress rapidly.
Concerns are more often raised about those who come from countries which may have been ravaged by wars or other forms of social disaster.
Children who aren't used to any kind of formal education can struggle to adapt.
As a general rule, the younger the children arrive in a school, the easier it is for them to learn English and adjust to the British system of education - but what if your child is not from a migrant family?
Christopher McGovern, the chairman of the Campaign for Real Education which aims to promote a greater emphasis on traditional values in state education, has concerns.
"The problem is not the migrant children. The problem is the white working class children who are doing very badly at school," said Mr McGovern.
"White working class boys are at the bottom of the educational pile and I think quite a lot of parents are afraid or fearful that because there's a lot of attention given to migrant children, perhaps rightfully, their own children are being neglected."
In recent years, experts say, there has been a new form of migration.
White British families and second-generation immigrants have been moving out of schools near urban centres to more distant suburbs, or into the countryside.
That's a process which raises its own deep questions about the future of education in our cities.