Almost as soon as the news broke that Diana, the estranged wife of the heir to the British throne, had been killed when a chauffeured Mercedes crashed in the Pont de l'Alma tunnel in the French capital, the conspiracy theorists came out of the woodwork.
Killed by MI6
Diana was not the only one who died in the crash.
Her boyfriend Dodi Al-Fayed and their chauffeur, Henri Paul, were also killed. Bodyguard Trevor Rees-Jones was the only one to survive.
A few months later Dodi's father Mohamed al-Fayed, an Egyptian businessman who at the time owned Harrods department store in London, began claiming the crash was not an accident.
He claimed his son and the princess were killed by MI6 on the orders of her father-in-law, the Duke of Edinburgh, husband of the Queen.
French police and Scotland Yard said they found no evidence of such a plot but the 88-year-old reportedly still nurses his pet theory.
Rees-Jones was interviewed four times by the French authorities but had only vague memories of the crash.
"I am not part of a conspiracy to suppress the truth at all. All I have ever done is give the truth as I see it," he told the inquest.
She Was Pregnant
Mohamed al-Fayed also alleged the princess was pregnant with his son's child.
In 2007, the Daily Express, a British newspaper which carried almost daily stories about the princess for years afterwards, published a story claiming to have seen a document by a French surgeon who carried out the post-mortem, which said she was nine weeks pregnant.
The document, which was unearthed by a "top French investigative journalist," was allegedly found in the archives of the Pitie-Salpetriere Hospital, where the dying princess was taken.
The Express claimed the document was sent to three French government ministers.
But John Burton, the royal coroner who was present at the post-mortem, was quoted in the same month in a different newspaper saying the exact opposite.
"She wasn't pregnant. I have seen into her womb," he told the rival Daily Mail.
At the inquest, which concluded in April 2008, the coroner Lord Justice Scott Baker said it could never be conclusively proved whether or not she was pregnant but he said was taking a contraceptive pill at the time of her death.
She Was About to Marry a Muslim
Diana had only met Dodi about nine weeks before her death, in the south of France, but there have been persistent reports that the couple were engaged.
Dodi was 42 and a divorcee. Ironically earlier in 1997 he had proposed to an American model before jilting her when he met the princess.
31 August 1997. 12:14 AM. Princess Diana and Dodi Al Fayed prepare to leave the Ritz Hotel with driver Henri Paul. pic.twitter.com/VwfWSvF8JT— Prof.Frank McDonough (@FXMC1957) August 31, 2017
At the inquest Mr. al-Fayed accused Prince Philip and other members of the Royal family of plotting to kill Diana to prevent her marrying a Muslim man.
In 2011, the Express (yes, them again) reported that a German journalist, Trixi Chall, claimed she had seen the couple pick out an US$15,000 (£11,500) engagement ring in a shop in Monte Carlo, and the paper claimed it was sent to their suite at the Ritz hotel in Paris just hours before they died.
At the inquest a former royal bodyguard, Michael Faux, claimed the ring had been removed from Diana's cold, dead hand by her former butler, Paul Burrell, who totally refuted the claim.
Driver Was Not Drunk
Those who believed the numerous conspiracy theories did not buy the story that the crash had been simply due to a driving mistake by a chauffeur, Henri Paul, who was under pressure from paparazzi on motorbikes and also inebriated.
Henri Paul shouts at Jacques Langevin to get out of the way.pic.twitter.com/xrOTl0odAP— Diana Day by Day (@DianaDaybyDay) August 30, 2017
Conspiracy theorists claimed Mr. Paul was a double agent for either French or British security services, or both.
They claimed he had been paid large sums of money and this cash was held in 15 separate bank accounts.
Operation Paget, the investigation led by former Metropolitan Police commissioner Lord Stevens, concluded his wealth had not come from the security services.
His father Jean, who lives in Brittany, said he believed his son's blood samples, which showed he was over the legal alcohol limit, had been tampered with.
The bill for the table occupied by Henry Paul and the two bodyguards at the bar is closed.— Diana Day by Day (@DianaDaybyDay) August 30, 2017
It records the two Ricard served to Henri Paul. pic.twitter.com/qqkUed9Pck
"My son was simply collateral damage of a plot to kill Diana and they killed him as well," he told the Daily Mirror.
But Lord Stevens' investigation stated he had drunk the equivalent of ten small glasses of pastis, a popular French spirit flavored with aniseed, before driving that night.
The inquest jury decided the crash was "caused or contributed to by the speed and manner of the driving of the Mercedes… and the impairment of the judgement of the driver of the Mercedes through alcohol."
The fact that Diana and Dodi were not wearing seatbelts was also considered a contributory factor by the inquest jury.
The 'Bright Light Theory'
Several witnesses reported seeing a "significant flash of light" moments before the crash.
Francois Levistre, who was driving in front of the Mercedes, said the light was "like the light from a police speed camera."
Former M16 agent Richard Tomlinson told the inquest her death resembled plans he saw in 1992 for the assassination of Yugoslav President Slobodan Milsoevic by using a bright light.
Tomlinson was jailed under the Official Secrets Act after he gave a synopsis of his proposed book, about his MI6 career, to an Australian publisher.
The former head of MI6, Sir Richard Dearlove, told the inquest a proposal was made to assassinate a senior politician in the Balkans by forcing a car crash in a tunnel was considered in the early 1990s but was rejected.
The paparazzi who were following Diana on motorbikes would, of course, have needed flash lighting to take pictures in the tunnel but that was too simplistic an explanation for the conspiracy theorists.
The Mystery White Car
Forensic analysis of the wrecked Mercedes reportedly showed it had come into contact with a white Fiat Uno.
French police eliminated 4,000 Fiat Unos and never identified the car.
The wreckage of the car is loaded onto a truck and taken away in front of the world's media for forensic examination pic.twitter.com/FjPWC0IKGQ— Diana Day by Day (@DianaDaybyDay) August 31, 2017
Mr. al-Fayed claimed the car had been driven by a French photographer, James Andanson, who he claimed was also a secret service agent.
Andanson was found dead in a burned out BMW in May 2000.
But another theory has it that the white Uno was driven by former security guard Le Van Thanh.
Mr. Thanh has refused repeated requests from Lord Stevens to discuss what he may or may not know.
In 2006 however, his father claimed Mr. Thanh resprayed the car red a few hours after the accident.
She Is Still Alive
The wackiest conspiracy theory of them all (so wacky that even the Daily Express has ignored it) is that Princess Diana faked her own death in order to live in blissful peace away from the paparazzi.
In order to believe this theory you would need to accept that not only was she willing to deceive her own sons, Prince Harry and Prince William, who were then aged 12 and 15, but that Dodi also fooled his own father into believing he was dead.
But in 2012 novelist Monica Ali published a book, Untold Story, which imagined a princess — never actually named as Diana — faking her death and ending up living a quiet life in small town America.