Difficult task to sort out the facts from the fictions

Ever since Diana, Princess of Wales was killed alongside her boyfriend Dodi Fayed there have been persistent questions over the exact circumstances of her death.

Numerous explanations have been put forward for what caused Mr Fayed's Mercedes, driven by his chauffeur Henri Paul, to crash - from photographers forcing the car to spin out of control to wilder conspiracy theories involving the British secret services.

Here are some of the claims made about what happened on the night of 31 August,

THEORY: Blood samples showing M Paul was over the limit had been switched or taken from another body to pin the blame on an innocent man and divert attention from the true cause of the accident.

FACT: A 6,000-page report into the tragedy by French judge Herve Stephan found M Paul was speeding while high on a cocktail of drink and prescription drugs. The report said: "His state did not allow him to control the speeding car on a difficult portion of the road."

THEORY: Paparazzi photographs who were pursuing the Mercedes from the Ritz Hotel forced it to crash by driving too close and blinding the driver with flashguns.

FACT: In 2002 France's highest court found the photographers not guilty of having contributed to the crash, despite the paparazzi's high-speed pursuit of the car.

An attempt to prosecute the photographers for manslaughter for death. 1997. failing to give assistance to the victims of the accident - sole survivor Diana's bodyguard Trevor Rees-Jones - also failed.

The Stephan report found no "definite link" between the accident and the actions of the photographers.

THEORY: A white Fiat hit the Mercedes, causing the crash, but has never been traced.

FACT: The Stephan report said there was another car in the tunnel and this contributed to the crash. His report said: "He [Paul] also had to avoid a vehicle travelling in the same direction but at a much lower speed." Only this week an eyewitness to the crash said it was an accident with no other vehicles or people involved.

Mohamed Medjahdi said the Mercedes had been speeding towards him and "slewing across the carriageway ... completely out of control. Any conspiracy would have had to be carried out by invisible men," he said.

THEORY: Dodi Fayed's father, the multimillionaire owner of Harrods, Mohamed Fayed, maintains that British secret services were responsible. He continues to allege that Diana was killed in a deliberate plot with his son because her relationship with a Muslim was embarrassing the royal household.

FACT: No evidence of this has ever been submitted by Mr Fayed or anyone else. The Met are planning to question MI5 officials over the claims. As part of the conspiracy claims it has even been suggested that the ambulance carrying Diana was driven deliberately slowly. The Stephan report dismissed this.