The inquest into the death of Diana, Princess of Wales in 1997 will not be heard by a jury, the coroner has said.
Princess Diana and Mr Al Fayed died when their car crashed in 1997
Lady Elizabeth Butler-Sloss had been considering sitting with a jury made up of members of the public.
But she decided to hear the case alone after scrutinising legal arguments delivered at the High Court last week.
Mohamed Al Fayed, whose son Dodi died with the princess in Paris, said it was a "shocking but predictable" decision not to have a jury at their inquest.
The inquest is expected to be held in May.
Lady Butler-Sloss's decision follows an earlier announcement in which she rejected having a jury made up of members of the royal household.
In a 34-page document, she considered the arguments in favour of sitting with a public jury.
She pointed to the assertion she would be perceived as biased because she gave her backing to Lord Stevens's report into the deaths - which dismissed many of the conspiracy theories surrounding the crash.
But she denied any allegations of bias.
Lady Butler-Sloss says a "fully reasoned decision" is needed
She accepted that the "intense public interest" in the deaths had to be taken into account - but said it could be used in arguments for or against having a jury.
"The disadvantage of a jury is the need in these inquests to have a careful and fully reasoned decision reviewing all the relevant evidence and providing a clear conclusion as to by what means and in what circumstances the princess and Dodi Al Fayed died," she said.
"Such a reasoned decision can only be given by the coroner and cannot be given by a jury."
But Mr Al Fayed said: "The public, and in particular, a jury of ordinary people must hear all the evidence, in front of an independent and fair-minded coroner."
He said he has instructed lawyers to take "all possible steps" towards achieving a public jury.
The Stevens report concluded that the crash, in the Pont de l'Alma tunnel in Paris on 31 August 1997, was a tragic accident, and that driver Henri Paul was drunk and driving too fast.
Mr Al Fayed maintains the couple were murdered and claims their deaths were part of a secret plot by the British establishment.
At least 40 witnesses will give evidence at the full inquest.