When the anniversary comes, later this month, few will be in the mood to look back. All the political talk will be of the Makerfield byelection, of the future of this government and this prime minister. And yet, it would be wise to reflect on what happened on 23 June 2016 – if only because the choices Keir Starmer and his would-be successors face, indeed the entire political and cultural landscape we now inhabit, are informed or were shaped by that event. We are living in Brexit Britain.