EXPERTS investigating what caused a whale to swim hundreds of miles off course before getting stranded in the river Orwell today revealed they had been unable to uncover why it got lost.

EXPERTS investigating what caused a whale to swim hundreds of miles off course before getting stranded in the river Orwell today revealed they had been unable to uncover why it got lost.

Tests conducted by the Institute of Zoology in London have shown that the six-metre northern bottlenose - which rescuers named George - was suffering from dehydration, muscle damage and kidney failure.

They said today the results from blood tests had confirmed predictions that the whale suffered classic fatigue-related symptoms in the hours before its death under the Orwell bridge.

Samples of blood were taken from the whale after rescue attempts failed and it was given powerful sedatives as it lay stranded in the shallows on the Orwell Country Park side of the river.

The results of the tests on those samples are now back and a spokeswoman for the Institute of Zoology said they showed George suffered a similar fate to Wally - the northern bottlenose whale which was at the centre of an ambitious rescue attempt after it swam up the Thames to London last year.

The spokeswoman said: “It's similar to the Thames whale in that it was suffering from dehydration, muscle damage and kidney failure. They are what you expect to happen when they get lost.

“When they strand their muscles get weak and toxins go into their kidneys and cause them to shut down in the long run.”

But what the tests failed to give was any clues why it lost its way, probably from its feeding grounds off the coast of Norway.

“There's nothing in the test results to tell us why it got stranded,” the Institute of Zoology spokeswoman said.

After George was first spotted in the Orwell on the afternoon of Friday, July 27 a rescue operation coordinated by the British Divers Marine Life Rescue volunteer group was mounted.

However experts said the fate of the whale was virtually sealed by the time it entered the North Sea because of the lack of the deep sea squid northern bottlenoses feed on.

It was the lack of the squid which led to the whale suffering dehydration, because the mammals get their liquid through their food.

George died early on July 28 after spending a night stranded on the mud banks of the river.

The stranding will now form part of a detailed study being conducted into why whales sometimes go off course.