Forty miles from the nearest Scottish inhabitants lies the remote island of Borelay, one of the most inhospitable places on the planet. Ringed by a treacherous coastline and pounded by furious seas it was always clear to experts why Borelay was devoid of settlements.

Except it wasn’t. Archaeologists have found evidence that prehistoric people once lived on the island. How did they get there? How did they survive? The answer may be lost in the mists of time.

Or maybe they went there because no one told them they couldn’t.