For over two centuries, the 'Irish question' has dogged UK politics. Though the Good Friday Agreement carved a fragile peace from the bloodshed of the Troubles, the Brexit process has shown a largely uncomprehending British audience just how uneasy that peace always was – and thrown new light on Northern Ireland's uncertain constitutional status.

Remote from the British mainland in its politics, economy and cultural attitudes, Northern Ireland is, in effect, in an antechamber, its place within the UK conditional on the border poll guaranteed by the peace process.

As shifting demographic trends erode the once-dominant Protestant–Unionist majority, making a future referendum a racing certainty, the reunification of Ireland becomes a question not of if but when – and how.

In this new, fully updated edition of A United Ireland, Kevin Meagher argues that a reasoned, pragmatic discussion about Britain's relationship with its nearest neighbour is now long overdue, and questions that have remained unasked (and perhaps unthought) must now be answered.