The EU referendum was intended to answer, once and for all, the thorny question of Britain’s relationship with the European Union. But instead it has brought to the fore many even more fundamental questions. The status of Scotland within the United Kingdom is once again a pressing issue. Concern is growing over the open border between Northern Ireland and the Republic of Ireland, and with it the future of the Good Friday Agreement. The divide in values and outlook between a prosperous greater London and the rest of England, itself underscored by longstanding economic disparities, has become a looming chasm. Jennifer Jackson-Preece explains whether nationalism is to blame for these divisions