An author given access to the official French report on the death of Britain's Princess Diana was quoted as saying it dismissed "fevered speculation" about her fatal car crash and final emergency care.
Martyn Gregory, writing in Britain's Daily Mail newspaper on Saturday, said he had seen the 6,000-page police report during his research for a television documentary on Diana's death in Paris in 1997.
He quoted one ambulance official as telling the report: "Diana had no chance of making it."
"The accident was too violent. The internal injuries she suffered were incompatible with life," the official added.
Diana, whose marriage to Prince Charles broke down in 1992 and ended in divorce, was killed with her lover Dodi al Fayed and driver Henri Paul after their car hit an underpass pillar.
A summary of the French inquiry was released in 1999, concluding the crash was caused by Paul being drunk and driving too fast.
The report will be part of the evidence considered by Royal Coroner Michael Burgess and Britain's most senior policeman John Stevens, who are conducting an official British inquiry into Diana's death.
The French findings failed to silence Dodi's father, Mohamed al Fayed, owner of London department store Harrods, who alleges Diana was killed in a deliberate plot with his son because their relationship was embarrassing the royal household.
Gregory, who has written two books about Diana's death, said the report dispelled claims that the ambulance which took her to hospital was driven deliberately slowly to reduce her chances of surviving.
He said medics quoted in the dossier said Diana had suffered a heart attack at the scene of the early morning crash and that problems with her blood pressure meant she was too ill for the ambulance to go any faster.
It took an hour and a three-quarters to get Diana to hospital, where she died at 4 am after suffering a second heart attack.
Gregory said the report also disproved claims that the blood samples which showed Paul was three times over the French drink-drive limit had been switched or taken from another body.
Gregory told the paper the report deployed "the full and painstaking armoury of modern investigative techniques which address all of the fevered speculation that has arisen".