In Poplar in East London, the beats of Tweet - America's latest rap star - echo through the estate.

Dee's Girls, a youth group for girls only, has been running for two months now. It's a place where girls can hang out, chat, dance and play pool - away from the lads.

I can't say that all black people are like one thing or all Asian people like something else. You can get black people, white people, Asian people, whatever, but they all act as urban people Nicola, 14

The girls are Somalian, African, Jamaican, Moroccan and White European. They are all British and are mostly into R'n'B, rap and hip hop.

For Dee's Girls, their different colours are simply not an issue. What brings them together is their common culture of the street.

"I can't say that all black people are like one thing - or all Asian people like something else," says Nicola, 14. "It's about upbringing: where you come from and your area. You can get black people, white people, Asian people - whatever - but they all act as urban people."

This fusion of styles can be heard on any radio station. Rap samples bangra; rock uses rap; R'n'B goes pop; and pop goes Asian (think Holly Valance). Life as one great musical masala.

But it's not just music and dance that have been changed by these multi-cultural influences.

No surprises

In Poplar, the girls chat about the difference between Muslim and Christian weddings - while planning a fashion show celebrating black and Asian styles.

Dee's: Girls from all backgrounds

And they can regularly be found round at each others' houses, eating the traditional ethnic dishes cooked by their mums - with the Moroccan food served up by Raja's family the current favourite.

None of this surprises Dr Anoop Nayak, who has published extensively on racial identities and youth culture.

He believes that life has changed radically in the past twenty years.

"Many of today's young people are growing up in multi-cultural areas where they live, go to school, and form lasting friendships with children from diverse ethnic backgrounds.

"In these multi-ethnic urban areas, multi-culturalism can be a way of life."

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Indeed, his latest research has found that where young people live and belong is often more important than their colour - with an unusual result.

"These changes can result in even stronger attachments to those places, localities or nationhoods where ethnic minorities are often construed as the harbingers of socio-economic unrest."

As Nicola says: "Pop acts like Britney Spears, they've come from wealthy backgrounds.

"But R'n'B and hip hop artists are from lower or working class backgrounds. Eminem - he grew up there, he's part of it, he's been where we are."

Common experiences

The process is also being sped up by new technologies - like the internet.

In one 'virtual community' project, a group of young people link up through e-mail.

Some have never met, but became firm e-buddies by talking, learning, and sharing information and advice.

Dance club: Drawing on all styles of music

The fact that they were an ethnically diverse group was almost irrelevant. What linked them were their common experiences of modern urban life.

The anonymity of radio can also yield surprises.

Who, listening to Radio One rap guru Tim Westwood, assumed he was black?

In fact he is a middle-class white boy, who convinces millions each week of his rap credentials thanks to a street dialect coloured heavily with Afro-Caribbean slang.

This linguistic fusion is now a familiar dialect spoken by young people in cities across Britain.

But the blurring of boundaries created by this multi-culturalism is causing some concern that different cultures could lose their distinctiveness.

Many schools are responding to the challenge - with uniforms getting one of the most dramatic makeovers.

At one school in North London, they've abandoned the one-size-fits-all approach.

Instead, black, Asian and white girls are given a broad overall style to work from, and encouraged to customise it according to their culture and religion.

So you'll see Asian girls in trousers and braids, and Jamaican girls in short skirts and bindis.

No big deal

It's a cross-fertilisation which everyone seems comfortable with.

For many children growing up in Britain today, multi-culturalism is not a big deal. It's part of the fabric.

Young people regularly e-mail CBBC Newsround Online - and these two on the subject are typical.

"It is important that we learn to mix with others of different cultures to stop racism. Without black people you wouldn't have R'n'B and without white people you wouldn't have garage," says Shana, 12.

And Katy, 12, sums up the daily experience for millions of other young people: "If we didn't have different cultures Britain just won't be Britain."