He has turned up in corporeal form in Stockholm and in Oxford, in Sao Paulo and in Yerevan, in Cairo, in Los Angeles and, in female form, in Barcelona. No matter the country, there will always be a "raver".

His – or her – question goes like this. Why, if you believe you're a free journalist, don't you report what you really know about 9/11? Why don't you tell the truth – that the Bush administration (or the CIA or Mossad, you name it) blew up the twin towers? Why don't you reveal the secrets behind 9/11? The assumption in each case is that Fisk knows – that Fisk has an absolute concrete, copper-bottomed fact-filled desk containing final proof of what "all the world knows" (that usually is the phrase) – who destroyed the twin towers. Sometimes the "raver" is clearly distressed. One man in Cork screamed his question at me, and then – the moment I suggested that his version of the plot was a bit odd – left the hall, shouting abuse and kicking over chairs.

Usually, I have tried to tell the "truth"; that while there are unanswered questions about 9/11, I am the Middle East correspondent of The Independent, not the conspiracy correspondent; that I have quite enough real plots on my hands in Lebanon, Iraq, Syria, Iran, the Gulf, etc, to worry about imaginary ones in Manhattan. My final argument – a clincher, in my view – is that the Bush administration has screwed up everything – militarily, politically diplomatically – it has tried to do in the Middle East; so how on earth could it successfully bring off the international crimes against humanity in the United States on 11 September 2001?

Well, I still hold to that view. Any military which can claim – as the Americans did two days ago – that al-Qa'ida is on the run is not capable of carrying out anything on the scale of 9/11. "We disrupted al-Qa'ida, causing them to run," Colonel David Sutherland said of the preposterously code-named "Operation Lightning Hammer" in Iraq's Diyala province. "Their fear of facing our forces proves the terrorists know there is no safe haven for them." And more of the same, all of it untrue.

Within hours, al-Qa'ida attacked Baquba in battalion strength and slaughtered all the local sheikhs who had thrown in their hand with the Americans. It reminds me of Vietnam, the war which George Bush watched from the skies over Texas – which may account for why he this week mixed up the end of the Vietnam war with the genocide in a different country called Cambodia, whose population was eventually rescued by the same Vietnamese whom Mr Bush's more courageous colleagues had been fighting all along.

But – here we go. I am increasingly troubled at the inconsistencies in the official narrative of 9/11. It's not just the obvious non sequiturs: where are the aircraft parts (engines, etc) from the attack on the Pentagon? Why have the officials involved in the United 93 flight (which crashed in Pennsylvania) been muzzled? Why did flight 93's debris spread over miles when it was supposed to have crashed in one piece in a field? Again, I'm not talking about the crazed "research" of David Icke's Alice in Wonderland and the World Trade Center Disaster – which should send any sane man back to reading the telephone directory.

I am talking about scientific issues. If it is true, for example, that kerosene burns at 820C under optimum conditions, how come the steel beams of the twin towers – whose melting point is supposed to be about 1,480C – would snap through at the same time? (They collapsed in 8.1 and 10 seconds.) What about the third tower – the so-called World Trade Centre Building 7 (or the Salmon Brothers Building) – which collapsed in 6.6 seconds in its own footprint at 5.20pm on 11 September? Why did it so neatly fall to the ground when no aircraft had hit it? The American National Institute of Standards and Technology was instructed to analyse the cause of the destruction of all three buildings. They have not yet reported on WTC 7. Two prominent American professors of mechanical engineering – very definitely not in the "raver" bracket – are now legally challenging the terms of reference of this final report on the grounds that it could be "fraudulent or deceptive".

Journalistically, there were many odd things about 9/11. Initial reports of reporters that they heard "explosions" in the towers – which could well have been the beams cracking – are easy to dismiss. Less so the report that the body of a female air crew member was found in a Manhattan street with her hands bound. OK, so let's claim that was just hearsay reporting at the time, just as the CIA's list of Arab suicide-hijackers, which included three men who were – and still are – very much alive and living in the Middle East, was an initial intelligence error.

But what about the weird letter allegedly written by Mohamed Atta, the Egyptian hijacker-murderer with the spooky face, whose "Islamic" advice to his gruesome comrades – released by the CIA – mystified every Muslim friend I know in the Middle East? Atta mentioned his family – which no Muslim, however ill-taught, would be likely to include in such a prayer. He reminds his comrades-in-murder to say the first Muslim prayer of the day and then goes on to quote from it. But no Muslim would need such a reminder – let alone expect the text of the "Fajr" prayer to be included in Atta's letter.

Let me repeat. I am not a conspiracy theorist. Spare me the ravers. Spare me the plots. But like everyone else, I would like to know the full story of 9/11, not least because it was the trigger for the whole lunatic, meretricious "war on terror" which has led us to disaster in Iraq and Afghanistan and in much of the Middle East. Bush's happily departed adviser Karl Rove once said that "we're an empire now – we create our own reality". True? At least tell us. It would stop people kicking over chairs.