A 30ft-long model of Nessie that sank to the bottom of Loch Ness 50 years ago has been found by an underwater robot.

The model was built for the 1970 movie The Private Life of Sherlock Holmes but was lost at the end of production when it was dismantled.

It has now been rediscovered nearly 600ft below the surface of the loch by researchers using an underwater robot.

Scientists from Norwegian firm Kongsberg Maritime carried out details surveys of Loch Ness earlier this year in an attempt to learn more about the mysterious body of water near Inverness.

They have ruled out claims there could be an unexplored "Nessie trench" at the bottom of the loch but discovered the 27ft-long wreck of an unidentified boat.

Kongsberg subsea engineer Craig Wallace said: "Kongsberg first surveyed Loch Ness with some of the world's first multi-beam sonar back in 1987 and have continually visited bringing the latest technology to uncover this Loch's mysteries.

"Our robot is the most advanced low logistic autonomous underwater vehicle (AUV) in the world and is the first in the next generation AUVs from Kongsberg Maritime.

"Merging the cutting edge technology from the commercial sector whilst maintaining the robust reliability from the military market, the vehicle provides insight to the loch's deeps never before imagined.

"The vehicle allows sonars to scan just a few metres from the loch floor, giving resolution several orders of magnitude greater than anything before."