A mystery explosion has blasted a large crater on an uninhabited Shetland island.
The 20ft crater was found by crofter and fisherman Arthur Polson on the tiny island of Mooa, off Whalsay, where he lives.
At first Mr Polson, 65, who grazes sheep on Mooa, thought the hole was caused by the ground falling into a cave that runs under the island.
But he said: "I just wonder if there was an explosion in the cave, perhaps caused by something floating in on the tide."
