Met chief: I'll check every theory

Sir John Stevens this afternoon stood in the Paris underpass where Princess Diana died and promised to "draw a line" under the case with a new investigation.

The Met Commissioner studied photographs and plans in the tunnel as he retraced Diana's final journey as part of a £2 million Scotland Yard inquiry into the 1997 tragedy.

He pledged to investigate "every single conspiracy theory" in relation to the deaths in a car crash of Diana, Dodi Fayed and their driver Henri Paul.

He said: "We have to try to do everything we can one way or another to draw a line under this inquiry.

"There are a lot of conspiracy theories surrounding the tragic deaths of these three people. It is my job to report to the coroner every single aspect of this investigation in order to prove or dispense with these theories once and for all." He added that his team of 10 detectives was planning to interview MI6 and MI5 officers in connection with claims by Harrods owner Mohamed Fayed that the security services were responsible.

Sir John dismissed claims that his trip to Paris was unnecessary and a publicity stunt, adding: "You cannot possibly get a feel for the evidence by looking at photographs and video evidence and reading witness statements.

"You have to come to the scene and this trip has been invaluable.

"For a start we have found that the gradient leading into the tunnel is much deeper than we thought."

Sir John was briefed by Martine Monteil, head of the equivalent of the Paris CID. He spent 15 minutes in the tunnel accompanied by royal coroner Michael Burgess who ordered the fresh investigation. He also visited the Ritz hotel in Paris where Diana and Dodi stayed. Sir John went to the suite the couple shared and stood at the spot where they got in their car.

Escorted by French police, Sir John and his team followed the route Diana and Dodi took to the Pont d'Alma tunnel where the car crashed.

A two-year French investigation concluded that the driver, high on drink and drugs, was responsible for the crash by driving too fast as they tried to escape photographers.

Police sources said Diana's sister, Lady Sarah McCorquodale, and Mr Fayed were being kept informed of any developments.

There have been numerous theories over the death of Diana.

The controversy was fuelled when her former butler Paul Burrell revealed the existence of a letter from the Princess in which she said she thought her husband was plotting to kill her in a car accident.

Sir John plans to interview Prince Charles over the allegations contained in Diana's handwritten note. Other key figures due to be interviewed are Dr Hasnat Khan, the heart surgeon who became Diana's secret lover.