There was "no conspiracy or cover up" in the car accident that killed Princess Diana and Dodi Al-Fayed nine years ago, the official report has concluded.
Former Metropolitan police commissioner Lord Stevens said that after a three-year, £3.6 million probe, he believed the Paris crash was simply a "tragic accident".
However, Mohammed Al-Fayed rejected the report as "complete rubbish" and said he continued to believe that the intelligence services murdered his son and Princess Diana.
Launching the report today, Lord Stevens said he had "personally ensured that every reasonable line of enquiry has been undertaken in order to evaluate fully any evidence that might support this extremely serious allegation".
His investigation team interviewed more than 300 witnesses and viewed more than 600 exhibits. Two new eyewitnesses not located by the French investigation into the crash had also been found and questioned.
He rejected the main claim behind the conspiracy theories, that Princess Diana was pregnant and that the British establishment could not let her marry Dodi Al-Fayed, a Muslim, and also said the couple were not engaged at the time of the crash.
Mr Al-Fayed had bought an engagement ring and intended to ask the princess to marry him at some point, but Lord Stevens said that from talking to close friends and family, he did not believe she was or had any intention of getting engaged at that time.
Today's report also argues that any attempt to use a car crash to kill the couple was highly unlikely. It says the events of the night of the August 30th changed considerably from the original plans, because of the paparazzi interest, and could not have been foreseen.
"The car, the driver and the point of departure all therefore changed within a very short space of time," Lord Stevens said.
"This left no opportunity, in my opinion, for anyone to put into action any plan, particularly one that would have required so much preparation and so many people to effect it."
He said the British government, including the intelligence services, had given him their "full cooperation and assistance" and he had personally examined MI5 and MI6 records.
Lord Stevens rejected reports that there was a flashing light set off in the tunnel where Princess Diana died, and although he acknowledged that her car had had "glancing contact" with a white Fiat Uno just before it crashed, said this was not significant.
When the car entered the tunnel it was going at between 61 and 63 miles per hour. The driver, Henri Paul, who also died, was twice over the drink drive limit and Lord Stevens expressed confidence that the blood sent for testing was indeed his.
"I do not believe that any evidence currently exists that can substantiate the allegation of conspiracy to murder that has been made," Lord Stevens concluded.
"Various legal cases are being pursued by Mr Al Fayed through the French courts. They are unlikely, in my opinion, to have any bearing on my conclusion that there was no conspiracy or cover up."
However, Mr Al-Fayed told Today ahead of the publication of the report that he would not accept its findings, saying: "I don't trust [Lord Stevens]. I will ignore it because it is complete rubbish. He has betrayed me and he has betrayed the country."
He claimed the evidence in the Stevens report was "made up", saying that the blood tested as Henri Paul's blood was actually that of a suicide victim. He added: "There are so many unanswered questions."