Among extraordinary details due to emerge in the report by former Metropolitan police commissioner Lord Stevens is the revelation that the US security service was bugging her calls in the hours before she was killed in a car crash in Paris.

In a move that raises fresh questions over transatlantic agreements on intelligence-sharing, the surveillance arm of the US has admitted listening to her conversations as she stayed at the Ritz hotel, but failed to notify MI6. Stevens is understood to have been assured that the 39 classified documents detailing Diana's final conversations did not reveal anything sinister or contain material that might help explain her death.

Scotland Yard's inquiry, published this Thursday, also throws up further intelligence links with the Princess of Wales on the night she died. The driver of the Mercedes, Henri Paul, was in the pay of the French equivalent of M15. Stevens traced £100,000 he had amassed in 14 French bank accounts though no payments have been linked to Diana's death.

Stevens's conclusion is that Diana, her companion Dodi Fayed, and Paul himself died in an accident caused by Paul driving too fast through the Pont de l'Alma underpass in Paris while under the influence of drink. The car was being pursued by photographers at the time.

Tests have confirmed that Paul was more than three times over the French drink-drive limit and was travelling at 'excessive' speed. The inquiry will quash a number of conspiracy theories that have circulated since 31 August 1997, among them that Diana was pregnant. It also found no evidence that the princess was planning to get engaged to Dodi, son of Mohamed Fayed.

The Harrods tycoon believes that Paul's blood samples were swapped to portray him as a drunk in an elaborate cover-up by the establishment to stop Diana marrying Dodi, a Muslim.

Stevens is expected to concede that while there was a mix-up it was an accident and that the original French post-mortem which found that Paul was three-times over the French drink-drive limit was correct.

He is also expected to discount the role of the white Fiat Uno which struck Diana's car shortly before the crash, even though British police officers have failed to track down the vehicle which left paintwork on the black Mercedes.

The inquiry will support the findings of the original French accident inquiry in criticising the paparazzi as a possible reason for encouraging Paul to speed. The 'bright light' theory - the claim that the driver was deliberately blinded by a beam immediately before the crash - is also dismissed by Stevens.