Diana, Princess of Wales was killed because she planned to expose senior members of the British arms trade involved with land mines, a leading lawyer claimed today.
Michael Mansfield QC, who represented Mohamed al-Fayed in the inquest into the death of his son Dodi and the former royal, said Diana claimed she had an "exposure diary" in which she was going to unmask the people most closely involved with the British manufacturing of land mines.
He told the Hay Festival in mid Wales: "I think everyone remembers she raised the profile of the land mines.
"Everybody is aware that the British involvement in the arms trade, particularly land mines, is and was a huge vested interest.
"It seems to me she had planned various visits. She had already been to Angola, she was going to Cambodia later in the year.
"She was going to set up an institute for the victims of the land mines that had been exploded."
He added: "A large number of land mines had been manufactured by the British and I think, and a witness who knew her well claimed, that she had an exposure diary in which she was going to expose the people most closely involved in the British arms trade. It seems to me that is not unrelated (to her death)."
Mr Mansfield said there is a missing box of papers which could contain crucial information.
He said: "Nobody really knows what was in it. The box exists but when it was opened there was nothing in it and everybody has forgotten what was in it.
"I don't know what was in it. It is said there were papers in there, it may have been the diary or notebook she was keeping in relation to the arms trade or it may be other correspondence between the royal family and herself."
Mr Mansfield said he believed the car crash in Paris in 1997 was "more than a mere accident" when he first heard about it.
He said: "Two people so vilified suddenly end up in a crash. I started to ask questions about who does this benefit, how did this come about?
"I got asked to do the case from a different channel and they didn't know I was already very interested in the opportunity, which very few of us ever get, to get senior security service chiefs and senior politicians in a witness box.
"I felt very strongly there was more to this case than a mere accident."
He added: "The verdict of the jury was not accidental death. The jury had that option and chose not to take it, they came back to unlawful killing contributed to by the paparazzi and following vehicles.
"The interesting thing is most immediate vehicles were driven not by paparazzi but people they have never managed to trace."
When asked how he distanced himself from conspiracy theorists, Mr Mansfield said: "I think most people think I'm a lunatic and that's fine.
"I'm not a conspiracy theorist about everything and there is cock-up as opposed to conspiracy but it's a very healthy analysis. It gets you to ask questions you wouldn't otherwise ask."