When middle-class social scientists like Michael Young in the 1950s and 1960s discovered what a high attachment people in working-class communities had to stability and continuity it was considered something to celebrate by left-wing sociologists. When people objected to that continuity being disrupted by the churn of mass immigration they were denounced.  

And, since becoming sensitised to this issue, I too often hear old-fashioned class snobbery from elite, even left-wing professionals with their mobile "achieved" identities towards the little people with their greater attachment to place and group. Recently, for example, a well-known liberal newspaper columnist told me how pleased he was that the boring lower-middle-class suburb he was raised in had been disrupted by big demographic change against the wishes of the existing population. 

But it was the senior civil service economist who told me straight-faced that it was his job to maximise global welfare, not national welfare, who finally prompted me to begin writing my book in 2009. It is one thing to believe in relatively open economic flows, but quite another to imagine one is living in a post-national world of undergraduate fantasy.

The book partly reflects my thinking since "Too Diverse?", but is also the result of the many visits I made over a two-year period to the areas of high minority settlement in Britain to try to attempt a rough audit on the successes and failures of the great immigration experiment. This was an ambitious, even hubristic goal but surely a worthwhile one. 

The debate has certainly shifted in a more realistic direction since 2004. The reception of my book has been calm and reasonable compared with the screams of pain that greeted my essay. I have had a mix of favourable and unfavourable reviews, from both Left and Right, almost always on the basis of what the reviewers' pre-existing beliefs on the subject were. In the almost ten years between the essay and the book, two things in particular have helped to mature the debate. First, it has become far easier to separate arguments about racial justice from the economic and cultural arguments surrounding large-scale immigration. Second, it has become possible to talk more openly about the very different outcomes for Britain's main minority groups in terms of their own internal cultures rather than the blanket racism of British society.

I hope I have contributed in a small way to the greater openness of discussion about some of these matters. And I hope the debate can become even less taboo-ridden; racism has been in sharp decline in recent decades but there remains plenty of fear and anxiety associated with race and how swiftly the country is changing. Many people worry that a more open debate that also encompasses the failures and mistakes of recent times only gives succour to extremists. I disagree.