A British police inquiry has concluded the car crash that killed Diana, the late Princess of Wales, was an accident — dismissing conspiracy theories that have swirled for years.

"Our conclusion is that, on the evidence available at this time, there was no conspiracy to murder any of the occupants of that car," John Stevens, the former head of London police who led the inquiry, said Thursday.

This security camera image shows Diana arriving at the Ritz Hotel in Paris on Aug. 30, 1997, hours before she was killed in a car crash.
(APTV/Associated Press)

"This was a tragic accident."

Diana, 36, her companion Dodi Fayed, 42, and chauffeur Henri Paul were killed when their Mercedes crashed in the Pont d'Alma tunnel in Paris on Aug. 31, 1997, while the couple was being pursued by photographers. Bodyguard Trevor Rees-Jones was seriously injured.

Stevens said Paul, whose blood-alcohol level was twice the British legal limit at the time of the crash, was drunk and driving at twice the local speed limit before the car crashed.

"We can say with certainty that the car hit the curb just before the 13th pillar of the central reservation in the Alma underpass, at a speed of 61 to 63 miles [98 to 101 kilometres] per hour," Stevens said.

"Nothing in the very rapid sequence of events we have reconstructed supports the allegation of conspiracy to murder."

A French judge came to the same conclusion, ruling in 1999 that the crash was an accident and the chauffeur was drunk.

Last-minute change in plans helped rule out murder

The inquiry was set up to assess whether there was credible evidence to support allegations of conspiracy to commit murder, including a number of claims made in legal documents and public appearances over the years by Fayed's father, Mohammed al Fayed.

Al Fayed alleged the couple was killed because of a conspiracy by the British establishment, including Prince Philip and intelligence agencies.

But Stevens said the attention of photographers earlier in the evening led Diana and Fayed to change their travel plans later in a short space of time, which did not leave any opportunity for anyone to put a murder plan into action.

Diana was 'not about to get engaged': inquiry

He also said the inquiry is certain that Diana was not pregnant at the time of her death, and was not engaged or about to become engaged to Fayed — two frequent allegations by those who didn't think the crash was accidental.

According to Mohammed al Fayed, his son phoned before the couple left the hotel to say he was planning to propose to Diana and had an engagement ring.

'We believe she never saw that ring.'—John Stevens, on whether Dodi Fayed proposed to Diana

But Diana's eldest son, Prince William, who was interviewed by the inquiry, said she had not "given the slightest indication" that she was about to become engaged to Fayed.

"We believe she never saw that ring. I don't know whether Dodi was going to ask her to marry him that night," Stevens said. "From the evidence of her close friends and associates, she was not engaged and not about to get engaged."

Mohammed al Fayed said in an interview before the report was released that he will reject its findings, accusing Stevens of having been blackmailed into changing his conclusions.

"I will ignore it because it is completely rubbish. And I will answer and he will really get the right answer. He will understand that he betrayed me," he said.

The inquiry, which involved 15 police personnel and is estimated to have cost several million dollars, used cutting-edge computer technology to reconstruct the crash scene and examined the wrecked Mercedes in painstaking detail.

Investigators talked to 300 witnesses, collected 600 exhibits, travelled to Paris to see the site of the crash, and interviewed Diana's former husband, Prince Charles. The inquiry also located and interviewed two new eyewitnesses.

'I have seen nothing that would justify further inquiries with any member of the Royal Family.' —John Stevens

Stevens said there was "no cover-up" in Diana's death.

"I'm satisfied that no attempt has been made to hold back information and we are confident that the allegations made are unfounded," Stevens said.

"I have seen nothing that would justify further inquiries with any member of the Royal Family," Stevens added.

Diana's sons supported the findings. Princes William and Harry "trust that these conclusive findings will end the speculation surrounding the death of their mother Diana, Princess of Wales," according to a statement from Clarence House, their father's office.

Report to be posted online

The 832-page inquiry report will be made available on the internet, Stevens said.

"Three people tragically lost their lives in the accident and one was seriously injured. Many more have suffered from the intense scrutiny, speculation and misinformed judgments in the years that have followed," Stevens said.

"I very much hope that all the work we have done and the publication of this report will help to bring some closure to all who continue to mourn the deaths of Diana, Princess of Wales, Dodi al Fayed and Henri Paul."

With files from the Associated Press