Diana crash witness: I saw a dozen 'shady figures' in tunnel

Record producer Jacques Morel, 59, is convinced they expected to see her Mercedes brought to a halt by another car.

Detectives working on the inquiry into Diana's death, headed by former Scotland Yard chief Lord Stevens, considered his account so important that he was flown to London and interviewed for three days.

Mr Morel, who was driving home with his wife Moufida in Paris on the night of August 31, 1997, said: "As we entered the Alma tunnel I looked to my left and saw about a dozen shady figures on a tiny pavement by the side of the opposite carriageway.

"They were all standing in a long line. The sight was unforgettable.

"The pavement is less than 30cm (12in) wide and next to fast traffic. They would have been breathing in petrol fumes and it was very dirty down there. It was certainly not a sensible place to stand around."

If accurate, Mr Morel's recollections are significant because they suggest that the route Diana and Dodi Al Fayed were taking was known in advance.

Until now it has always been thought that chauffeur Henri Paul was following an unexpected route in order to shake off paparazzi photographers.

Mr Morel, who now lives in Tunisia, said: "There was an almighty bang and a great big flash of light. Immediately my wife and I realised there had been a crash.

"My first thought was that those inside the tunnel were connected with what had happened. This thought has never left me.

"We could see a car coming from the opposite direction had gone straight into a pillar. All of the other drivers stopped, so I did too.

"There was a symphony of car horns and then white smoke filled the tunnel. I got out of my car and rushed towards the crash scene.

"I was devastated when I saw the Princess in her white trousers in the back of the car. She was easily recognisable.

"She looked so serene and peaceful, but it was the end. It was one of the most heartbreaking scenes of my life. I will never forget seeing her face.

"Others were lying around Diana and I remember the driver looking as though he had his head in his hands. It was then that I also saw a white Fiat Uno being driven away."

The car was later reported to be registered to James Andanson, a paparazzi photographer who committed suicide in mysterious circumstances in 2000. However, the vehicle has never been found.

Mr Morel, who has written a book about his experiences, told British detectives Philip Easton and Mark Hodges that he believes Paul was in on the plot.

"I am certain he was paid to drive through the Alma tunnel. There was cash in Henri Paul's pocket when he was found dead,' said Mr Morel.

Blood tests revealed that Paul was three times over the French drink-drive limit when the crash took place. Traces of anti-depressant drugs were also found.

The inquiry headed by Lord Stevens, which has taken 1,500 witness statements, is expected to deliver its report by Christmas.