In Chapter 4 we tell the story of how identity conflicts were first mobilised into electoral politics during the first wave of migration to Britain after the Second World War. This period of British history is rarely mentioned in conjunction with our decision to leave the EU in 2016, but it is critical for understanding more recent identity conflicts. The first wave of sustained mass migration was the first demonstration of the disruptive power of such conflicts, producing a wave of ethnocentric voter mobilisation which upended political competition and has continued to reverberate in debates over multiculturalism, discrimination and identity ever since. The new political conflicts generated more recently by another surge in immigration have interacted with, and sometimes reinforced, these older divisions. The paths followed by Labour and the Conservatives on such issues were first traced out in this period, with Labour establishing themselves as defenders of ethnic minorities, and the Conservative choosing to mobilise anti-immigrant sentiments in the white majority. We cannot understand the identity conflicts mobilised by Cameron, May and Farage without first understanding the era of Heath, Powell and Thatcher.