Leatherback numbers are under pressure (Image: Matthew Godfrey)

The 2.75m-long (9ft) creature was found near Harlech, more than 7,500km (4,700 miles) from its birthplace in the West Indies.

BBC Wildlife magazine reports a new study that suggests leatherbacks should be viewed as a UK/Irish species which simply visits the Caribbean to breed.

Five of the world's seven turtle species, many of whose numbers are in decline, can be seen off the UK coast.

The Harlech leatherback has been put on display at the National Museums and Galleries of Wales in Cardiff.

The animal weighed more than 900kg (2,000lbs) and, at 100 years old, it was the oldest recorded turtle as well as the largest.

Sadly, it was found dead in 1988 after it drowned whilst trapped by fishing lines.

More and more leatherbacks are being spotted around the coast of Britain and Ireland, suggesting the turtles are trawling our waters for their favourite food - jellyfish.

Following the Welsh discovery, marine ecologists at Swansea University and University College Cork used satellite-tracking systems to follow 10 leatherbacks from their nesting sites in the tropics.

Re-classification

Contrary to expectations, the tracking showed the turtles did not stay long in the Caribbean, but spent most of their time in food-rich northern waters, including those around the British Isles.

More work on the study is now underway in the Irish Sea but Peter Richardson, of the Marine Conservation Society, hopes it will lead to leatherbacks being re-classified as British/Irish - so improving the species' chances of survival.

Turtle numbers have been in serious decline worldwide because of coastal redevelopment, egg-snatching, pollution and fishing.

Long-line fishing alone is believed to kill about 50,000 leatherbacks a year when they become accidentally caught on hooks.