So obscure is Heligoland these days that one needs a keen historical or geographical knowledge, or experience as a sailor, to know very much about it. To the uninitiated it sounds like the home of some harmless tribe that was railroaded into a European empire during the Scramble for Africa. In fact, it is a tiny, rocky island in the North Sea on the approach to the Elbe. In this utterly fascinating book, Jan Rüger reminds us of the island’s huge significance during the 19th and the first half of the 20th centuries, and of how it came to be a sort of windswept symbol of Anglo-German relations.

In 1807 the British, fearing that the Danes, who controlled the island, would allow it to be taken by the French (who would then have had a strategic stronghold in the North Sea at the height of the Napoleonic Wars), moved in to occupy it and declare it a colony.