A Corsica-sized naval base in the North Sea

Who would control a Corsica-sized island in the middle of the North Sea, and how would it affect naval history?

Britain would most likely control it by the twentieth century and use it as a major naval base and blockade position close to Germany.

A Corsica-sized island in the North Sea would be fought over for centuries by Denmark, Norway, Britain, and other regional powers. Britain would probably occupy and retain it before the twentieth century. Its area could support a major fleet base much closer to Germany than Scapa Flow. During the First World War it could anchor the distant blockade. The base would also make German raids against Britain's east coast far more hazardous because the raiders would have to pass a British force on their return route.