At around 4.35 last Monday morning, my Beirut mobile phone rang in my Tehran hotel room. “Mr. Fisk, I am a computer science student in Lebanon. I have just heard that students are being massacred in their dorms at Tehran University. Do you know about this?”

When I arrived at the university, the students were shrieking abuse through the iron gates of the campus. “Massacre, massacre,” they cried. Gunfire in the dorms. Correct. Blood on the floor. Correct. Seven dead? Ten dead, one student told me through the fence. We don’t know. The cops arrived minutes later amid a shower of stones. Filtering truth out of Tehran these days is as frustrating as it is dangerous.

I have been spending at least a third of my working days in Tehran this past week not reporting what might prove to be true but disproving what is clearly untrue.

Take the call I had five hours before the early-hour phone call, from a radio station in California. Could I describe the street fighting I was witnessing at that moment? What I could see were teenagers on motorcycles, whooping with delight as they set light to the contents of a litter bin on the corner of the highway.

Two policemen ran up to them with night-sticks and they raced away on their bikes with shouts of derision. Then the Tehran fire brigade turned up to put out their 79th litter-bin fire of the night. I knew how he felt. A report that Basiji militia had taken over one of Mousavi’s main election campaign office was a classic. Yes, there were uniformed men in the building — belonging to Mousavi’s own hired security company.

Now for the very latest on the fantasy circuit. The cruel “Iranian” cops aren’t Iranian at all. They are members of Lebanon’s Hezbollah militia. I’ve had this one from two reporters, three phone callers (one from Lebanon) and a British politician. The reality is that many of these street thugs have been brought in from Baluch areas and Zobal province, close to the Afghan border. Even more are Iranian Azeris. Fantasy and reality make uneasy bedfellows, but once they are combined and spread with high-speed inaccuracy around the world, they are also lethal. Sham elections, the takeover of party offices, a massacre on a university campus, an imminent coup d’état, the possible overthrow of the whole 30-year old Islamic Republic, the isolation of an entire country as its communications are systematically shut down.

But the no-smoke-without-fire brigade has a point. Look at the extraordinary, million-strong march against the regime by Mousavi’s supporters on Monday. Even the Iranian press was forced to report it, albeit on inside pages. Yes, the authorities have indeed closed down the local SMS service. Yes, they have slowed down — but not closed — the Internet. My Beirut roaming phone now rarely reaches London, although incoming calls arrive round the clock. The Iranian government is obviously trying to interfere with the communications of Mousavi supporters to prevent them from organizing further marches. Outrageous in any normal country, perhaps. But this is not a normal country. It is a state as obsessed with the dangers of counterrevolution as the West is obsessed with Iran’s nuclear ambitions. The supreme leader’s speech yesterday was proof of that.

We have, in fact, reported all the censorship — of local newspapers as well as communications. The footage of a brutal police force assaulting the political opposition on the streets of the capital has shocked the world. Rightly so, although no one has made comparison with police forces who batter demonstrators on the streets of Western Europe. There are special codes of morality to be applied to Middle East countries which definitely must not apply to us.

So let’s take a look at those Iranian elections. A fraud, we believe. And I have the darkest doubts about those election figures which gave Mousavi a paltry 33.75 percent of the vote. But our coverage of this poll has been deeply flawed. Few news organizations have the facilities or the time or the money to travel around this 659,278 square-mile country and interview even the tiniest fraction of its 71 million people. When I visited the slums of south Tehran on Friday, for example, I found that the number of Ahmadinejad supporters grew as Mousavi’s support dribbled away. And I wondered whether, across the huge cities and vast deserts of Iran, a similar phenomenon might be discovered. A Channel 4 television crew, to its great credit, went down to Isfahan and the villages around that beautiful city and came back with a suspicion that Ahmadinejad just might have won the election.

This is also my suspicion: That Ahmadinejad might have scraped in, but not with the huge majority he was awarded. Perhaps Ahmadinejad got 51 percent or 52 percent and this was preposterously increased to 63 percent. Perhaps Mousavi picked up 44 percent or 45 percent. I don’t know. The Iranians will never know, even though the supreme leader told us yesterday that the incredible 63 percent was credible. That is Iran’s tragedy.

Yes, Ahmadinejad remains for me one of those leaders which this region sadly throws up, to the curses of its friends and to the delight of its enemies in the West.

And those nuclear arms? How many of us reported a blunt statement which the supreme leader and the man who ultimately controls all nuclear development in Iran made on June 4, just eight days before the elections? “Nuclear weapons,” he said in a speech in which he encouraged Iranians to vote, “are religiously forbidden (haram) in Islam and the Iranian people do not have such a weapon. But the Western countries and the US in particular, through false propaganda, claim that Iran seeks to build nuclear bombs — which is totally false...”

There are few provable assurances in the Middle East, often few facts and a lot of lies. Dangers are as thick as snakes in the desert.