A spy vessel has been found near the UK's top secret Faslane nuclear submarine base, according to sources. Credit: Handout.

It reads like a Tom Clancy spy novel.

A mysterious autonomous surveillance “boat” is discovered off the coast of Scotland, and is reported to authorities.

Britain’s military and intelligence authorities respond — the unmanned “spy boat,” powered by solar energy, is feared to be part of a foreign espionage program.

Could it be Russia? No one is entirely sure — no country has stepped forward to claim it.

In a weird twist, some experts say it could even belong to the US Navy — the vessel does fit the description of the so-called “Wave Glider,” built by US firm Liquid Robotics.

The question is, who was operating it?

Could it be Britain’s Five Eyes American ally? Highly unlikely.

Scary scenario? The vessel was found very near the UK’s top secret Faslane nuclear submarine base.

And according to the Daily Express, UK navy officials are taking no chances.

They now fear that Moscow may now have acquired the “acoustic signature” of Britain’s nuclear submarines.

The autonomous vessel was found by beachcombers amongst the rocks on the island of Tiree last month. Officials say it was designed for stealth so as to avoid detection.

This mysterious surveillance boat was found on the Scottish island of Tiree by beachcombers. Credit: Handout.

The dark grey vessel did not have any navigation lights, which is a legal requirement for all ships at sea which and has led to suggestions it was on an intelligence gathering mission, The Sun reported.

Put it this way, an elite British naval unit has now deployed underwater drones off the high-security base at Faslane, where the UK’s Trident nuclear deterrent is based, The Express reported.

Counter-surveillance devices have also been placed around the Clyde estuary where the Trident submarines travel to the open sea.

The damage may have been done, however.

A UK defence expert told The Daily Mail: “Capturing the acoustic signature is quite the prize in the cat-and-mouse game of submarine hunting.

“The Russians know our four Trident boats are a potent threat and knowing exactly what they sound like can help pick them out in a noisy ocean.”

Commenting on the unusual discovery, a writer on website unexplained-mysteries.com commented: “Exactly where this one had come from and what it was doing still remains a total mystery and to date nobody has come forward to claim ownership of it.

“It is even possible that it ran aground while on some sort of secretive spy mission.

“If that were true however, it’s unlikely that any country will come forward to claim it.”

It is known that Russia has deployed an increasing amount of submarines throughout the world’s maritime regions, especially in the Arctic, The Express reported.

In 2019, no less than ten Russian submarines were deployed from their pens in the Russian Arctic coast, a NATO report confirmed.

Observers have stated this submarine exercise is the largest by Russia since the end of the Cold War, as Putin attempts to expand Russian naval power into the Atlantic.

— Sources: The Daily Mail, The Sun, Daily Express