In this classic text, first published in 1977, Tom Nairn memorably depicts the ‘slow foundering’ of the United Kingdom on the rocks of imperial decline, constitutional anachronism and the gathering force of civic nationalism. Rich in comparisons between the nationalisms of the British Isles and those of the wider world, thoughtful in its treatment of the interaction between nationality and social class, The Break-Up of Britain concludes with a bravura essay on the Janus-faced nature of national identity. Postscripts from the Thatcher and Blair years trace the political strategies whose upshot accelerated the demise of a British state they were intended to serve. As a second Scottish independence referendum beckons, a new Introduction by Anthony Barnett underlines the book’s enduring relevance.