THERE is much to be said about the deep, brooding waters of Loch Ness. But, of course, its chief story revolves around the elusive Nessie, a monster mystery worth, reputedly, around £41 million to the Scottish economy. Rarely a year goes by when there is not some news relating to the possible, but unproven, existence of the creature.

The latest claim came this April in the form of holiday-maker footage which appeared to show a large creature moving through the water, humps breaking the surface,. One Nessie expert, Garry Campbell, described it as compelling. But proof if is certainly not.

Meanwhile, Loch Ness, continues to draw hunters in their droves, the most persistent being 59-year-old Steve Feltham, who has dedicated over half his life to watching the waters.

Nessie’s most popular image is that of a long-necked plesiosaur, a marine dinosaur which went extinct 65 million years ago. But one of the questions that has hung over the plesiosaur hypothesis has been that they were thought to have only lived in the sea. However, a study published last month revealed that fossils of small plesiosaurs had been discovered in a 100-million-year-old freshwater river system now part of the Sahara desert.

The researchers, from the University of Bath, were quick to point out the significance of this for the Nessie question – perhaps spotting a bit of monster clickbait for their own study. “What does this all mean for the Loch Ness Monster?” they said. “On one level, it’s plausible. Plesiosaurs weren’t confined to the seas, they did inhabit fresh water.”

But plesiosaurs, they noted, died out with the rest of the dinosaurs. One of the authors of the study, Nick Longrich, also pointed out that for all Loch Ness’s extraordinary depth, it’s too small to support a plesiosaur. “How would they exist undetected?” he asked. “Something like a plesiosaur, it’s large. It’s conspicuous. It has to surface and breathe air. If they existed, people would see them come up for air.”

Of course, the plesiosaur theory is just one of many.. As Charles Paxton of the School of Mathematics and Statistics, University of St Andrews, points out, “ I know of 1,452 distinct encounters. Only about 20 percent of the reports mention a neck of any length, so it is not the monster’s normal form...So I think it reasonable to assume that whatever the reported phenomena of the Loch Ness monster is founded on, it is not based on glimpses of a prehistoric reptile.”