KEY POINTS:
A New Zealander's evidence could form a crucial piece of the puzzle as the world waits to hear the true story behind the death of Diana, Princess of Wales.
Richard Tomlinson, a renegade British secret service spy who was born in Ngaruawahia, is due to give evidence to the Royal Courts of Justice in London during the inquests into the 1997 deaths of the Princess and Dodi Al Fayed.
Lord Justice Scott Baker, who is heading the inquests, has listed 20 key issues that he will focus on.
And one of those is whether Mr Tomlinson's evidence throws any light on the collision.
Mr Tomlinson, a highly controversial figure who worked for MI6 and was later sacked by the organisation, claims the Princess' death was curiously similar to a fate planned by MI6 for Serbian leader President Slobodan Milosevic in the early 1990s.
He also claims the Princess and Al Fayed's driver, Henri Paul, who was also killed in the crash, worked for MI6.
In an affidavit Mr Tomlinson gave to a French magistrate investigating the deaths in 1997, he said: "Whatever MI6's role in the events leading up to the death of the Princess of Wales, Dodi Al Fayed and Henri Paul, I am absolutely certain that there is substantial evidence in their files that would provide crucial evidence in establishing the exact causes of this tragedy."
Mr Tomlinson's evidence is among the most eagerly anticipated, particularly among people who believe there is evidence of a high-level conspiracy behind the Princess' death.
His evidence to the coroner's court is based on documents he saw when he was still a part of MI6.
He claims that in 1992 he was shown a three-page outline plan to assassinate Slobodan Milosevic, as Yugoslavia descended into civil war.
One of three scenarios was to cause his car to crash by disorienting the driver using a strobe flash gun.
The plan also involved arranging the crash in a tunnel so there would be more chance of death of serious injury and less chance of independent, casual witnesses, Mr Tomlinson claims.
The coroner's court hearing began on Tuesday and is expected to last four months. The court and an 11-member jury will visit Paris on Monday and Tuesday next week, with trips to the scene of the crash, the Ritz Hotel and the Pitie Salpetiere Hospital where the Princess was treated.
Mr Tomlinson also claims that Henri Paul was on the payroll of MI6.
His affidavit says he read the personal file of an MI6 informant working at the Ritz Hotel, where Paul was deputy head of security. "I cannot claim that I remember from this reading of the file that the name of this person was Henri Paul, but I have no doubt with the benefit of hindsight that this was he."
The former spy has had a chequered career.
A brilliant scholar, he made his way from Ngaruawahia to Cambridge University where he gained a double first degree in aeronautical engineering. He spurned the first advances from the British secret service when he was just 21, but joined up in his late 20s. He performed spectacularly, quickly outstripping other probationers in his intake.
He was with MI6 for almost four years when he was unceremoniously ousted in August 1995. His employers said Tomlinson was unreliable, not a team player and prone to disappearing. Tomlinson said he was unfairly dismissed after what was essentially a disagreement with his superiors.
His subsequent battle against the perceived injustice has made him very unpopular with the secret service, which has continued to monitor him closely and harass him across three continents, according to Mr Tomlinson.
Matters deteriorated further when he attempted to publish his memoirs. He was jailed for a year for breaking the Official Secrets Act before his book was finally released in 2001.
The Richard Tomlinson file
* Born: Ngaruawahia
* Educated: Cambridge University, England
* Recruited: British Secret Service 1991
* Operations: Smuggling advanced Soviet weaponry out of the former USSR. Unknown operations in Bosnia.
* Downfall: Sacked from MI6 in 1995
* Civilian: Arrested 11 times in five years and jailed for breaking Official Secrets Act
* Evidence: Claims Henri Paul was an MI6 informant and that a plot to kill Serbian leader Slobodan Milosevic was strikingly similar to the manner in which Diana, Princess of Wales died.
