Three hundred years ago, Scotland struck an extraordinary bargain with its English neighbour. Like all the best deals it involved giving away little – nominal sovereignty – in exchange for major gains: economic, political and cultural. Control over key domestic matters was retained. Today, that bargain, updated for the democratic era, is better than ever.

Nonetheless, a Scottish nationalist campaign of remarkable discipline has brought the United Kingdom to the point of extinction. This book sets out how to save it. It offers new political ideas and a clear set of rules to govern the constitutional debate. But above all, it urges those who wish to save the Union to explain that the bargain is not just a matter of money, or even sentiment about a shared past, but a canny and sophisticated arrangement that benefits all nations of the UK. It is the foundation of Scotland's success and unique place in the world.