It is possible that no one individual has ever set foot in both the northernmost and southernmost buildings in the British Isles. It happens that one is a lighthouse and the other a public toilet. They are, by our calculations, 1324 kilometres apart.

These are places on the edge, mere hints of human settlement on little island outposts that elide the attention of most cartographers. Insofar as these territories feature on maps at all, it is in boxed inserts on the margins of charts that give little hint of the real location of the islands in question. Do not a good percentage of the population of England really believe that the Shetland Islands lie somewhere off the east coast of Scotland, a delusion induced by a lifetime of television and newspaper weather maps that misrepresent the real location of this northern outpost?

So where are these buildings that mark the bounds of the British Isles?