Returning to America after an absence of 20 years, Henry James wrote, in The American Scene (1907), of his unease at the arrival in New York of so many non-English-speaking Jews from Europe. He observed them on the street, in shops and together in their neighbourhoods and ghettos, and feared not only for the future of America but for the English language itself, especially the language of literature. "There is no swarming like that of Israel when once Israel has got a start, and the scene here bristled, at every step, with the signs and sounds, immitigable, unmistakable, of a Jewry that had burst all bounds."

James was disconcerted by what he considered to be these new arrivals' sense of "settled possession", which he found "presumptuous, monstrous", and which contrasted with his own feelings of unsettled possession. He regretted how established Americans would inevitably be forced into a kind of surrendered acceptance of cultural difference. "We must go, in other words, more than half-way to meet them; which is all the difference, for us, between possession and dispossession. This sense of dispossession haunted me."

Following the often lurid debate about immigration and multiculturalism in this country, one sometimes feels that it is not the recent arrivals but the settled peoples of these islands who, like Henry James, feel most dispossessed, as if they are unable to understand, or feel powerless to prevent, what is happening around them.

But what exactly is happening? How rapidly and by how much is Britain really changing? We are ceaselessly told that ours is a multiracial and multicultural society. It is certainly multiracial--and all the better for it--but what does it really mean to speak of a multicultural society? Does a multicultural society mean simply a broad tolerance of difference and respect for minority cultures and traditions? Or does it mean something more assertive--the establishment, for instance, of more religious schools in Britain, of children being increasingly taught in separate religious and racial communities?

Early one Saturday afternoon at the end of February, I was travelling south on the London Underground from Tottenham Hale to King's Cross. Sitting opposite me in the carriage of our Victoria Line train were two women of Middle Eastern appearance. They were wearing the Muslim hijab or veil and speaking very quietly in Arabic, as if embarrassed at being overheard. In the same carriage were three young black women, who, judging from their conversation, were Nigerian. They were speaking "pidgin"--a vibrant, energetic hybrid of English and, I think, Yoruba. Their hair was worn in crisp braids and threaded with intricate wooden beads. Also in the carriage were two men in their twenties, one black and the other white. The white guy, I gathered, was from a Greek-Cypriot family, but his accent was entirely local. He and his friend were both clamorous Cockneys. Beneath their jackets, they were wearing Arsenal shirts.

At the next stop, a young woman, a poor Romanian or Albanian, entered the carriage. She was wearing a headscarf, a ragged shawl and cradled a baby in her arms. She held out her hand and patiently asked each person for money. Each time, she was ignored; at the next stop, she left the train, only to be replaced by a gang of about ten youths, who, I guessed from their dark hair and scruffy swarthiness, were from the southern Balkans. They were loud, they refused to sit down, and they spoke a language I did not recognise.

Watching these boys from the Balkans as they jostled and scrapped, I did not feel threatened or uncomfortable, but I did have a strong sense of how London was being changed by the new multiculturalism and by the arrival of hundreds of thousands of people from parts of the world that had little or no affiliation to the old empire. What was taking place deep underground on this Saturday afternoon was a characteristically contemporary London scene: boisterous, polyglot, multiethnic, harmonious.

But it would not have been possible seven years ago: the forces of globalisation, more porous borders, the disintegration of Yugoslavia, the need for cheap labour, Islamic militancy, inexpensive air travel, and a second wave of mass, asylum-driven immigration mean that this is not the country it was when Labour returned to power in 1997. Something fundamental about the country has changed and is continuing to change, with theresult that it is perhaps no longer possible, indeed comprehensible, even to speak of a common British culture. Instead, we have a multiplicity of cultures, some complementary, others discrete or rivalrous.

The majority culture--anglophone, tolerant, broadly liberal, sceptical, Christian in ethos if not in practice--remains strong. But other cultures are threatening and subverting it, forcing concessions and change. Much of this change is good--such as the recognition of the rights of minorities or a respect for racial difference. But there are also areas of more problematic conflict, where the recognition of minority-group rights and identities, and the demand for exemptions from national laws, clash with a broader liberal consensus on, say, animal rights or women's freedom.

The new cultural clash is experienced most acutely in inner-city state schools, where children from so many different ethnic backgrounds, and for whom English is often a second language, are brought uneasily together. Education is the front line where teachers and governors fight daily culture wars, in a country that has an established Church, which privileges one religion and one culture, but also has a growing and increasingly assertive Muslim minority that demands equality and legitimacy for Islam.

Britain has a strong tradition of secular government. It has, as the philosopher Roger Scruton points out (above), managed to marginalise the Christian religion "by making it into a shy adjunct of the secular state", which has led to the withering away of religious instruction in many schools. But many Muslims, who view Islam as a revolutionary force in their lives, want their children to receive a religious education. For them, religion is not a once-weekly recreation; it is an entire politics for living.

In France, where there are perhaps six million Muslims (one-tenth of the population), the response from the state to the new multiculturalism has been to reassert the secular ideals of the Republic. This has led to the outlawing of the hijab and other obvious religious symbols in schools.

In multinational, multi-ethnic Britain, we are taught a kind of civic patriotism. From the melancholy long withdrawing roar of empire, we have learnt humility and restraint. Our sense of national identity is not based on ethnicity, on the cult of blood and soil or racial superiority. It is far more subtle and more allusive. The British way is one of resolute pragmatism, reactionary yet progressive, respectful of tradition and the accumulated wisdom of past generations, as embodied in our institutions, but also alert to the need for constant change. Our civil war was a very long time ago and our revolution was glorious.

We are not, as are the French, committed to revolutionary ideals of equality and liberty, which is why the hijab or indeed the turban would never be banned in British schools. Nor are we suspicious of the politics of the "communautaires"--communities that have separate and potentially separatist values from those of the Republic. All this, as well as the absence of a written constitution and the fragmentary nature of the British state itself, makes us endlessly adaptable--and flexible. This sense of adaptability, as well as of soft nationalism, explains in part why Britain has hitherto so successfully integrated so many new arrivals from the Caribbean, Africa, the Indian subcontinent and beyond.

The culture and the way of life of this nation, of any nation, are best understood not through grand political abstractions, but through its songs, jokes, customs, clothes, food, and games. There is something indefinable, even mystical, about national identity: we know what Britishness is, we would defend it under duress, but we would be hard-pressed to define it coherently.