Thirty years ago, Scotland was the centre of the UFO world.

The 1990s started with a photograph that has achieved almost folkloric status as one of the best images of an Unidentified Flying Object.

Then came a flood of sightings of mystery objects in a part of central Scotland which came to be known as the Falkirk Triangle.

These captured the world's imagination, attracting journalists from around the globe and leading to claims of conspiracies, cover-ups and cheap publicity stunts.

The truth may still be out there. It is certainly complicated. And three decades on, what actually happened is still the subject of passionate debate.