“The Last Night of the Proms is supposed to be a celebration of Britishness. But this year there is a crisis of national identity, as people in the arts confront the cruel act of self-harm that Brexit represents. Last year’s Leave vote in the EU referendum divided the country and threatened the unity of the UK. It also revealed a cultural fault-line, between the young and the educated who saw the advantages of membership of the EU, and older and less privileged people who felt excluded and used the referendum as a form of protest.”