A two and a half minute video captured on the shores of Loch Ness appears to show a large creature moving through the water.
Experts have called it the most compelling footage produced in the last 20 years of the hunt for the Loch Ness Monster.
The clip shows what humps look like breaking the surface of the water and something powerful floating and spinning underneath.
A powerful wave of water can be seen behind the unknown creature, floating just below the surface and only 150 meters from shore.
Gary Campbell, who has spent 26 years logging every credible sighting of Nessie, said it was the best footage he had seen in decades.
Said to represent Nessie’s head and neck, this famous photograph was taken in 1934 by London surgeon Robert K. Wilson while on holiday in Loch Ness. It was later classified as a joke
He added: “This is a really, really good sighting of something that is inexplicable in Loch Ness.”
The remarkable footage was shot by a professional couple in their early 50s who were on holiday in the Scottish Highlands.
They said they had no strong beliefs about Nessie other than being amused by anecdotes about previous sightings.
The husband and wife, who wish to remain anonymous, are keen to have their footage analyzed in the hopes it can help provide definitive answers as to the existence of the monster or what might inhabit the lake.
The woman said: “We were quite ambivalent about the Loch Ness Monster. We enjoyed the stories but didn’t necessarily believe in them.
“We would be very happy if someone analyzed the video. If it helps anyone figure out what’s down there, it would be our absolute pleasure. We would be glad.’
Another mysterious sighting linked to the alleged monster caught in Loch Ness in 2002
The woman woke up just after 6am on Monday and decided to snap some photos as the lake was so still its surface was like glass.
But after seeing something big moving in the water, she started filming with her iPhone and heard her say, “What on earth is that?” when her husband joined her to see what was transpiring.
The pair filmed for two minutes and 37 seconds, starting at 6.21am, as the mysterious creature – they estimated it to be between 20 and 30 feet in length – swam underwater, affording them tantalizing glimpses as it broke the surface.
It appeared to have at least one fin or limb that paddled underwater “like an oar”.
The woman also took several stills from the vantage point of her cottage on the hill opposite Urquhart Castle, about a quarter mile from the lake.
She added: “I really don’t know what it was in the water. It was something big. I don’t think it really reflects how big it was on the video.
“We don’t know what the creature was. It propelled itself with something. No fish would do that.
“You could see it much clearer than in the photos. The lumps or bumps or whatever that was kept disappearing underwater, but it was still pushing forward underwater.
“You could see something underwater, then it charged forward and turned around. From what we could estimate it was between 20 and 30 feet long. There was nothing else on the lake, no boats, nothing.”
Her husband said: “We were not here to look for the Loch Ness Monster, we wanted to enjoy the beautiful scenery.
“Something strange happened out there on the lake. Someone who is much more intelligent than us on a scientific basis can analyze it and if it adds something to the understanding of the phenomena or even inspires a bit of interest and fun in a world that is full of misery at the moment, then that can’t not be a good one thing.’
The footage has now been turned over to Mr Campbell, who maintains the official register of the Loch Ness Monster and contains only sightings that cannot easily be explained away. He has now officially logged the sighting of the couple.
Mr Campbell said: “In terms of video evidence, there have been two or three really good videos in the past but this is certainly one of the best of them.
“When something like that comes up that’s really inexplicable, that’s great.”
Photo of a mysterious object in Loch Ness taken by London student Jolene Lin in 2016. She described it as a large snake and is convinced it was the Loch Ness Monster
Mr Campbell described the footage as the best since August 2000, when Glasgow postman Bobbie Pollock filmed a three and a half minute video of an unidentified creature in the hole.
But dr Darren Naish, a zoologist and author of Hunting Monsters, said he doubted a monster would ever be found in Loch Ness.
Describing the new footage, he said: “We see two tiny black objects filmed from a great distance.
“They are nothing more than unidentifiable spots on the water and there is no indication that we are seeing anything particularly large or unusual in shape.
“Based on what boats look like from roughly the same position and distance, the objects must be small – I’m guessing less than 50cm long.
“I see no reason why it can’t be birds – probably ducks. The marks they leave on the surface look interesting, but marks of this type are common on the surface of the lake when conditions are right.”