In 1872, Queen Victoria’s son Prince Arthur borrowed her yacht and went on a jolly cruise to the most curious outpost of the British empire. He wrote home: “Dear Mama, it is very gratifying to find your German subjects so loyal.” In the midst of the North Sea, a few hours sail from Hamburg, the union flag flew above the cliffs of the island of Heligoland, whose 3,000 inhabitants could be forgiven for bewilderment about where their allegiance should lie.
The island was Danish until, in 1807, when Denmark was for a time Britain’s enemy, a squadron of the Royal Navy occupied its useful anchorage, declaring the German-speaking islanders British subjects “with all the universally known advantages peculiar to that character”. For the remainder of
