It had not been feeding at all, and as a result of not feeding there were bleeding ulcers in the stomach

Tony Patterson veterinary pathologist

A post mortem examination was carried out at the Marine Conservation Society's laboratory in Inverness to determine the exact cause of death.

Veterinary pathologist Tony Patterson, who carried out the examination, said: "The primary thing would be death from hypothermia.

"It had a lot of body fat but the temperature of the water would have meant that its metabolism would have slowed down so much that it would not have been able to utilise that."

Further investigation

He said that many of the turtles found in UK waters were juveniles who were "well off the beaten track."

Mr Patterson said that the turtle was likely to have a ready supply of plant and animal material from which to feed, but was so exhausted by the cold it could not eat properly.

The number of rare green turtles has fallen in recent years

Scientists now hope that DNA tests on the turtle may eventually enable them to work out where it came from.

Once their investigations are complete, the remains will be sent to the Museum of Scotland in Edinburgh.

Marine scientist, Bob Reid, said: "They are normally found in tropical and sub-tropical waters. This creature obviously got lost, by quite a bit.

"It happens very occasionally and is very rare. It is unusual one should end up in Scotland."

The number of rare turtles has been falling in recent years due to hunting for their meat and eggs, which are regarded as a delicacy in some countries.