As history this book is fine, but it says nothing that has not been said before. As cultural commentary it has been said better (mostly by the people quoted liberally throughout the book). As a blueprint, it does not address the concerns of the generation for which it claims to speak. The younger generation of non-white Britons does not need to rebrand or reinvent itself. Those who do not survey the landscape from the comfort of established institutions have no need to "Imagine the New Britain." We are too busy living it.

The book is full of grand pronouncements. The author, like a seaside conjurer, says: "I have shed the terms 'ethnic minority' and 'racial minority' for this book." But then she gives us a long list of those who should be defined as British Asian, or British Black or Mixed Race. This obsession with definition and categorisation can only perpetuate divisions; in any case, most of the categories are so wide as to be meaningless. Identity is a complex thing which deserves better.

Disagreeing with Yasmin is like disagreeing with a favourite aunt. At one level there is nothing to disagree about: how can any right-thinking person contest her well-intentioned platitudes? But it has to be done. She worries about being caricatured as a "soft-centred liberal," yet says that liberalism's failure to come to terms with Britain's new ethnic mix reveals a deep racism. This may explain why she used her column in the Independent recently to storm out of the Labour party, claiming that the government has "edited us out."

The book feels too much like a cut-and-paste job; it has its moments, but it could have been so much better. The discussion about Britishness and identity too easily descends into waffle. The blurb proclaims: "Multiculturalism is about more than world music and prize-winning novels from the Indian subcontinent... How can it be that in these devolutionary times the debate about identity speaks only of the four nations of Britain?"

What does this mean? That the ethnic minorities should define ourselves as some multi-coloured "fifth nation"? The fact is that the argument has been won. There is a multicultural consenus in Britain. This does not mean that racism does not still blight our streets and stalk the corridors of power, in ways more subtle than most people imagine. But what does Yasmin expect? Where in the world is this not the case?

It is time we acknowledged some basic truths; it is time we swapped soft-centred liberalism for tough-minded liberalism. Human beings, of all colours and classes, have a tendency to favour their own kind. But this tribalism or nativism encompasses a wide spectrum, from repellent (and illegal), violent xenophobia, to a feeling of social discomfort among strangers of a different kind. Moreover, tribalism does not have to be ethnically or culturally exclusive; for many people living in larger cities, those defined as part of the "tribe" might include those of different religious, national or ethnic backgrounds. More and more we make our own tribes; doing so is part of the definition of modernity. For many young Britons of all backgrounds their tribal icons would include the Asian Dub Foundation, Ian Wright and Talvin Singh's Anokha.

Tribalism may be a fact of life, but it can also offend against the basic rules of the liberal state: those who apply the principle of equality before the law-whether a policeman or an employer- must not favour their own kind, nor disfavour any other kind. But, equally, no one should feel compelled to join in our all-singing, all-dancing celebration of multi-ethnic Britain.

Michael Ignatieff has already expressed this usefully in Prospect (April 1999). Applying Isaiah Berlin's distinction between negative and positive liberty, Ignatieff says that modern multicultural societies should make a distinction between positive and negative tolerance. Everyone is required to sign up to negative tolerance: this means that people of all kinds must be free to go about their daily business without harrassment or discrimination. This, as Yasmin rightly reminds us, is far from being achieved; it is where most of the hard work on race issues still takes place.

But negative tolerance also acknowledges what we all know to be true: that many people-perhaps most people-feel uncomfortable with the "other." For all the blather about common values, values in our society are becoming increasingly diverse. This is not only (or even mainly) to do with race: it is more bound up with the decline of religion and authority in general-people are freer to choose the way they live than ever before, and many are taking advantage of that freedom. This makes some other people feel uncomfortable, and this discomfort cannot simply be dismissed as illiberal or reactionary. It is not good enough to say, as Yasmin says, that those who are unable to embrace the changes of the modern world should "respond to their unease by worshipping crystals."

Positive tolerance-actively embracing difference and cultural diversity-is still a minority taste in Britain. But this minority is becoming larger. Indeed, in most industrial countries history is on the side of positive tolerance. As ethnic identity is replaced by a more deracinated, privatised and abstract notion of citizenship, we all, in a sense, become outsiders. But we must sign up only to those core rules of negative tolerance which, in our mutual self-interest, make living together possible. This makes it easier to accommodate diversity. It may make it harder to sustain solidarity, but that is another story.

Yasmin does not seem interested in this debate. She is too busy recalling the simple battle cries of the 1960s and 1970s. She also takes a swipe at Peter Sellers (among others) for perpetuating damaging stereotypes-I suppose for films like The Party and songs like Goodness Gracious Me. In fact these are not examples of the blacked-up fool perpetuating the playground stereotypes that she assumes (and which were much more perniciously peddled in programmes like Mind Your Language or It Ain't Half Hot Mum). They are, rather, an attack on the danger of making facile assumptions, which is why her much-fêted Goodness Gracious Me team use it as their theme song. In The Party, when the hapless Hrundi V Bakshi (played by Sellers) is asked "Who the hell do you think you are?" he replies: "In India, we do not think... We know who we are." In Britain we know who we are, too, but in the context of a society which-thankfully-is no longer at all sure.

"Who Do We Think We Are?" (rrp£18.99) can be bought through Prospect Bookstore at £15.99 plus 99p p&p. Call 020 8324 5649