Investigators have begun the task of unravelling the mystery behind Donald Campbell's tragic attempt on the world water speed record.

The investigation is being carried out on his craft, Bluebird, which famously lifted from Coniston Water and disintegrated in 1967.

The boat was raised from its watery grave earlier this month and is being kept at a secret location on Tyneside.

It has been long assumed that the crash was caused by a combination of choppy water and the fact that the Bluebird was made lighter by Campbell's decision not to refuel between his first and second attempts.

Experts from the Government, and engine makers Rolls Royce, now have the chance to discover the truth.

Bill Smith, the Tyneside diver who led the recovery team, said: "We have carried out a small amount of preservation work on Bluebird.

"But we are not carrying out any large-scale cleaning of the craft until the experts have completed their investigations.

"We are concerned that to carry out more thorough work on the craft before the investigation is finished could lose vital evidence.

"However, we have re-established the Union Flag on the tail fin.

"The paint on this area is not the same paint on the rest of the craft, and it was beginning to peel.

"We have also made the compressed air canisters on the craft safe, as they were still full of air and dangerous."

He said there was no foundation in the rumours that Campbell's body was found at the bottom of Coniston.

"The forces involved in the crash were more than enough to fragment a body," he said.

"Then you consider the 34 years that have passed for the body to decompose and be covered by sediment. There wasn't much chance of finding Donald Campbell's body."