The storied hunt for the Loch Ness Monster has produced another twist, after a strange contraption was discovered by mistake more than a hundred feet underwater. The curious find was made a robotic submarine called Boaty McBoatface, which was carrying out routine trials in the large freshwater loch in the Scottish Highlands.

The UK's National Oceanography Centre (NOC) testing marine autonomous underwater vehicles for almost a decade, with Loch Ness making an ideal deep-water environment for tests because of the extreme depths found there, as well as its unique conditions, as per The Daily Record. The unmanned craft was undergoing testing when its propeller became snagged in the mooring of a mysterious camera trap system, thought to date back to the 1970s. The ingenious device consisted of a camera within a protective tube, set up to take pictures whenever sea creatures pulled at the bait line. 

It's thought to have been the work of the Loch Ness Investigation Bureau, a group established in the 1960s with the mission of proving the existence of the cryptozoological creature, affectionately known among enthusiasts as "Nessie".

The device is thought to have been lowered 180 metres underwater in the hopes of getting an elusive photograph of the mythical monster.

But though no footage of the Nessie was found, one of Boaty McBoatface's engineers did manage to develop a few images from the film - showing only the depths of the famous loch.

Adrian Shine, of The Loch Ness Project, an organisation that has been researching the famous lake since the 1970s, was key in establishing what the makeshift gadget was.

He confirmed it was likely one of several that had been deployed at the time, with three others lost during a gale. 

Mr Shine said explained the newly discovery is "an ingenious camera trap consisting of a clockwork Instamatic camera with an inbuilt flash cube, enabling four pictures to be taken when a bait line was taken".

"It is remarkable that the housing has kept the camera dry for the past 55 years, lying more than 130 metres (426 feet) deep in Loch Ness," he added.

Explaining why the loch is so well suited to testing their cutting-edge sub, Matt Kingsland from NOC said: "At 230m (754ft) deep, Loch Ness is an ideal location for testing our robotics, their sensors, and systems before they're deployed in the deep ocean to help answer the big questions we have."

He added:"While this wasn't a find we expected to make, we're happy that this piece of Nessie hunting history can be shared and perhaps at least the mystery of who left it in the loch can be solved."

The camera, its original film and protective tube, has now been handed over to The Loch Ness Centre in Drumnadrochit, close to where it was found.

Wider interest in the creature began in the 1930s when the first purported photographs were taken, though their authenticity has been questioned. Though its widely considered to be an urban myth, the tale of a prehistoric creature hiding in the Highlands continues to attract enthusiasts from around the world.