Multiculturalism - what exactly is it?

This weekend David Cameron said he thinks multiculturalism has failed in the UK.

So does living in a true multicultural society mean being British first and putting your culture second?

Or is it lots of people from different cultures living in harmony side by side?

Nicky Campbell hears from callers from a variety of ethnic backgrounds, as well as columnists and academics in the area - about what multiculturism means to them, if anything.