http://www.kenanmalik.com/essays/bergens_putnam.html
Most strikingly, people in more diverse society people are more distrustful not just of members of other ethnic groups but of their own, too. 'It's not just that we don't trust people who are not like us', Putnam says. 'In diverse communities, we don't trust people who do look like us.'
Or to put it another way, the real problem is not diversity or immigration but the political context in which we think about such issues - in particular, the
loss of belief in the possibility of universal values and of a common culture. This inevitably leads to civic disengagement and a sense of anomie - and is why greater diversity leads to greater distrust of everyone, whatever their ethnic or cultural background.