Normally an inquest takes place within months of a death. This one came after ten years, three coroners and millions of pounds of taxpayers’ money.
Not only did something extraordinary and tragic happen on the last day of summer in 1997 when Princess Diana, her companion Dodi Al Fayed and the driver Henri Paul, died in the crash in Paris; but something extraordinary has happened ever since.
There’s been ten years for conspiracy theories to evolve, mutate and grow ever more elaborate.
Ten years for officials to try to get to terms with a new phenomenon a truly modern conspiracy theory – developed on the internet, relayed on the mass media and eagerly consumed around the world.
We’ve had the initial two-year French judicial inquiry, then Lord Stevens’ Metropolitan Policy inquiry, Operation Paget, at a cost of £3.7m and now an inquest over six months and costing on a conservative estimate another £3.6m. The total cost to British taxpayers of investigating Princess Diana's death is expected to exceed £10m.
Lord Stevens said he hoped the clear verdict that Princess Diana and Dodi Al Fayed were unlawfully killed due to the "gross negligence" of driver Henri Paul and the paparazzi could bring “closure to what has been a traumatic event”.
Will the inquest verdict finally end the speculation? I doubt it.
Last night Mohamed Al Fayed refused to accept the verdict. He said both the French and the Metropolitan police inquiries were wrong and he insisted that Diana was murdered: "I'm not the only person who says they were murdered. Diana predicted she would be murdered and how it would happen.”
As tonight’s Conspiracy Files Special, produced by Diana Martin, shows new evidence has helped resolve some of the key questions.
For example, it's confirmed there definitely was a second car, a white Fiat Uno, which collided with the Princess’s Mercedes; all the evidence suggests Diana was not pregnant; and it's now acknowledged that her driver Henri Paul had definitely been drinking that night - he ordered and drank two Ricards in the Ritz bar, the equivalent of three measures of whisky.
The coroner said the inquest had served "an important purpose" by examining the conspiracy theories "in minute detail" through the evidence of more than 250 witnesses. Lord Justice Scott Baker concluded that there “is not a shred of evidence” to support the theory that Princess Diana was assassinated by MI6 or any other government agency. But with many important French witnesses refusing to appear before the inquest, some questions will remain unanswered.
Forensic scientists reviewing the toxicological evidence have not been able to explain high levels of carbon monoxide in Henri Paul’s blood samples - which some people claim is evidence that the samples were switched. And a key witness, the driver of the white Fiat Uno has still not been identified.
The investigative journalist Gerald Posner puts that down to the faults of the initial French inquiry. But he tells the programme conspiracy theories have a life of their own:
"When you present solid and credible evidence to somebody who has embraced a conspiracy theory it is extremely difficult to have them give up on their belief. They will claim the evidence you presented has been planted, tampered with, faked by the conspirators themselves. It’s almost impossible to get someone to change their minds."
So was it all necessary? Well yes if so many doubts persist about such a public figure.
We now have a verdict that Princess Diana and Dodi Al Fayed were unlawfully killed due to the actions of driver Henri Paul and the pursuing paparazzi. But should it all have taken ten years to get to this stage?
Of course officials in the UK are not alone in having to deal with counter theories.
In the United States nearly seven years on from 9/11 and yet despite tens of millions of dollars being spent on official inquiries the debate about what really happened on 11 September 2001 continues.
The final, or so it’s planned to be, official report has still to be published and it is due out this summer.
The subject is a third tower that collapsed that day. The 610ft (186m), 47-storey skyscraper collapsed in a few seconds but it was never hit by a plane. According to the official investigators it is the first and only skyscraper in the world to have collapsed solely due to fire.
Later this spring on BBC Two, The Conspiracy Files will report on World Trade Centre Building 7 – a building that has become a rallying cry for those who question the official account of what happened on 9/11.
How Diana Died: A Conspiracy Files Special will be broadcast on Tuesday 8 April 2008 at 1900 BST on BBC Two.