Perhaps my interest in long term social change come from having an older father. My dad had just turned 50 when I came along in 1980. He would tell us stories of the Britain of his youth, living without television or computers, where cars were rare and store shelves often empty. Rationing was a defining experience of his childhood, explaining the delight he took in grocery shopping, and perhaps also why he was so much shorter than all five of his sons. The conditions we grow up with shape who we are, and what we want. This insight is not new, but its implications are perpetually underestimated. Politics focuses relentlessly on the short run – the agenda for the week, the coming Parliament – while the social changes wrought as new generations rise and older generations fade away run over decades. Such changes escape our notice, most of the time. But in the long run they reshape everything. University expansion and mass immigration were two of the engines of change which transformed British society over the course of my father’s lifetime. His university experience made him part of a privileged elite – less than one in 20 of his generation attended university in the 1950s. My uncle’s experience was far more typical – he left school at 15 with no qualifications in order to support the family. As recently as the 1980s more than half of the British electorate had no formal qualifications, having left schooling as soon as they could. The Britain of my father’s wartime childhood was homogenously white and native born. This, too, changed dramatically over the course of his life, as mass migration first from the Commonwealth and then from Europe changed Britain into a multicultural immigrant nation. One of those immigrants was my peripatetic Dutch-born mother, who arrived in the late 1970s to work in the NHS, where she met and settled down with my dad. Foreign birth caused my mum few difficulties beyond some light-hearted teasing of her accent. It was a different story for my parents’ colleagues from the Caribbean, the Indian subcontinent and Africa. They faced covert and overt prejudice in the Britain of Enoch Powell, where many white voters regarded them as an alien and threatening presence. My first doctoral student interviewed retired South Asian doctors who came to Britain in the 1950s and 1960s. Their stories were full of frosty receptions, ambitions blocked, and quiet efforts by white superiors to channel them into more remote and less prestigious jobs. The story is dramatically different in the youngest generations today, where over four in 10 teenagers attend university. One in five of today’s British teenagers belongs to an ethnic minority group, with mixed ethnic heritage the largest and fastest growing identity of all. These changes are reflected in attitudes and identity attachments – today’s youngsters, whatever their heritage, are far less likely than their parents or grandparents to say that being born in Britain or having British ancestry matters for “being British”, far less likely to express any discomfort about mixed marriages, and far more likely to say that fighting racism is an important personal and political goal. While prejudice and discrimination still blight our society, attitudes have changed a lot, as can easily be established by looking up some of the sitcoms which played on British TV in the 1970s. Much of my research has focussed on understanding what all of this means for British politics. I began researching the politics of immigration in 2004, just as a new wave of migration to Britain from Eastern Europe began. I was struck how arguments over immigration had a political power which seemed out of all proportion with the actual impact of the arriving migrants. Many voters with little or no direct experience of immigration were, and are, prone to see new arrivals as a threat. The source of such feelings of threat is social identity. We are all attached to social groups, and imbue them with meaning and value. But one fundamental distinction between the declining demographic group of white school leavers and the rising groups of graduates and ethnic minorities comes in the content of their social identities, and how they draw the lines separating “us” from “them”. White citizens who didn’t attend university – particularly older ones – are more strongly attached to narrowly drawn social identities. They are much more prone to see immigrants and minority groups as a threat to the identities they value. White graduates – particularly younger ones – have more open and blurred social identities, which incorporate newcomers and minorities with little difficulty. Both white graduates and ethnic minorities tend to see the defensive, exclusionary and sometimes hostile reactions of white school leavers as a major social and political problem. It is this clash of identities and values which makes conflicts over immigration so potent. Both Enoch Powell and Nigel Farage tapped into the anxieties of...