Operation Paget, the Metropolitan Police inquiry led by Sir John Stevens into the deaths of Diana, Princess of Wales and Dodi Fayed, was a remarkable event. It was the first time in this country that the state has investigated a set of conspiracy theories. The report’s title page has it as “The Operation Paget inquiry report into the allegation of conspiracy to murder”; but it actually addresses all the conspiracy theories around the deaths, propagated chiefly by Mohammed Fayed. Most of this involved re-examining the French police investigation. This is, in itself, a quite remarkable event: I can think of no other occasion when the French state has allowed the British state to examine one of its investigations. Given the frequently prickly diplomatic relationship between Britain and France, there must have been some complex negotiations, presumably based on an understanding that the outcome would not be critical of the French inquiry.

So, was the Stevens team ever going to do anything but reaffirm the official verdict of death by drunk driver and no seat belt? Despite all Sir John Stevens’s assertions of his inquiry’s independence, that seems highly improbable. Nonetheless, they did examine all the major conspiracy theories, and in sometimes mind-boggling detail. The report illustrates the differences between a police investigation and one by the fourth estate. With time, money and the power of the law to make people talk, Paget shows the French police doing an infinitely more thorough job than journalists tend to do. Take the story of James Andanson, the French-domiciled British photographer who apparently was at the scene and apparently owned a white Fiat of the type which brushed against the Mercedes driven by chauffeur Henri Paul. Andanson was later found burned to death in his car. Suicide was the official verdict. Murder, says the conspiracy theory. Except the French police found that the Andanson Fiat was barely roadworthy, and, like Andanson, was not in Paris at the time of the crash. Furthermore, Andanson had been depressed and, however unlikely this sounds, before burning to death in his car he had talked of committing suicide by… burning himself to death in his car.

More centrally, was Henri Paul drunk? Paul’s blood chemistry is pored over for dozens of pages, many of which I barely understood. But here’s the list of the alcohol found in his flat: Crème de Cassis, Ricard, Suze, port, beer, red wine, champagne, Martini Bianco, vodka, Pinot, bourbon and fortified wine. To this add the presence in Paul’s blood of one of the drugs which is supposed to discourage alcohol consumption and what have you got? An alcoholic trying to control his drinking: plain as day, whatever his friends might have said.

The report reminds us that some of the Fayed theory – Henri Paul as an MI6 informant and the crash caused by a blinding light in the driver’s eyes – came from former MI6 officer Richard Tomlinson. Something else remarkable happened when the Paget team came to check out Tomlinson: they were given access to MI6’s computer databases. That they found nothing to support Paul being an MI6 informant is less surprising than their getting access to the computer files. One wonders how this was arranged. “Please can we come and rummage about in the most secret computers in the land?”

The report asserts: “[T]he Operation Paget officers are confident about the integrity of the results achieved from their interrogation of the databases”, but who would believe that their access, unprecedented though it was, guarantees that there was nothing there? How difficult would it be, after all, to hide incriminating files?

In what I have read of the report, it is in the Paget team’s dismissal of Tomlinson’s account of an MI6 plan to assassinate Serbian President Slobodan Milosevic using a blinding light that there may just be a whiff of hanky-panky. The report shows that in his original version of the Milosevic story, written before Di’s crash, Tomlinson did not refer to a blinding light; he remembered this later, after reading something which reminded him of it.

The Paget officers talked to MI6, which admitted – another remarkable event – that there had been a proposal to assassinate not Milosevic but another, unnamed, Serb politician. This plan, said MI6, was immediately dismissed (of course) because MI6 doesn’t do assassinations (of course). Paget quotes Tomlinson as agreeing that his identification of Milosevic as the target was mistaken. Tomlinson says: “The report put words in my mouth that I never used. I gave them detailed information about the Milosevic plan for an assassination… This is a crude attempt by the intelligence service to cover up the truth.”

Even thinking about killing a European head of state is an infinitely more sensitive issue for MI6 than dealing with fantasies about their assassinating Princess Di. But whom do we believe? Tomlinson or Paget?