While Mr Blair talks of victory in Iraq, the troops are afraid to go out at night

I was travelling into the Shia Muslim Iraqi city of Nasiriyah on Friday evening when three American soldiers jumped in front of my car. "Stop the car, stop the car!" one of them shouted, waving a pistol at the windscreen. I screamed at the driver to stop. He hadn't seen them step into the road. Nor had I. Two other soldiers approached from the rear, rifles pointed at our vehicle. I showed our identity passes and the officer, wearing a floppy camouflage hat, was polite but short. "You should have seen our checkpoint," he snapped, then added: "Have a good stay in Nasiriyah but don't go out after dark. It's not safe."

What he meant, I think, was that it wasn't safe for American soldiers after dark. Hours later, I went out in the streets of Nasiriyah for a chicken burger and the Iraqis who served me in a run-down cafe couldn't have been friendlier. There were the usual apologies for the dirt on the table and the lack of paper napkins, along with the usual grimy square on the wall where, just two months ago, a portrait of Saddam Hussein must have been hanging.

So what was going on? The "liberators" were already entering the wilderness of occupation while our masters in London and Washington were still braying about victory and courage and - here I quote Tony Blair on the same day, addressing British troops 60 miles further south in Basra - of how they "went on to try to make something of the country you liberated".

Only a few hours earlier, one of Ahmed Chalabi's militiamen in Nasiriyah had shouted at me that the Americans there were "humiliating" the people, of how "they made a man crawl on all fours in front of his friends just because they didn't obey their orders". There would be a revolt if this went on, he warned.

Now I don't know if his story was true, and I have to say that every Shia I spoke to in Nasiriyah spoke warmly of the British soldiers further south, but something has already gone terribly wrong. Even the local museum guard who had earlier been travelling in my car had spoken of oil as the only reason for the war. "One hundred days of Saddam were better than a day of the Americans," he roared at me.

I don't think that's true - the Americans weren't slaughtering this man's fellow Shias by the tens of thousands as Saddam did 12 years ago - but it's a new "truth" that is being written here. Washington may hope that the charnel-house of corpses now being dug out of the desert to the north will provide a posthumous new reason for the recent conflict. "Now the truth can be told... " But we knew that truth a long time ago, after George Bush Senior called on these same poor people to fight Saddam and then left them to be butchered.

"Saddam was a shame upon Iraq," one man told me as we stood beside more than 400 skulls and bones in a school hall near Hillah. "But America let them die."

In reality, the lies that took us to war in Iraq are slowly being stripped away from the men who sent the American and British armies to Mesopotamia. Mr Blair could turn up in Basra this week with his sub-Churchillian rhetoric about "valour", with his talk of "bloodshed and real casualties" and his sorrowful refrain for the British soldiers "who aren't going back home". But who sent the British to die in Iraq? If they were "real casualties", what happened to the weapons of mass destruction that were so real when Mr Blair wanted to go to war but which seem to be so unreal the moment the war is over?

Mr Blair says we'll still find them and we must be patient. But Donald Rumsfeld, the US Secretary of Defence, tells us they may not have existed when the war began. The domestic repercussions of all this continue in London and Washington, but the reaction in Iraq is far more ominous. New graffiti on the wall of the slums of Baghdad's Sadr City (formerly Saddam City) which I saw on Wednesday tells its own story. "Threaten the Americans with suicide killings," it said bleakly.

It isn't difficult to see how this anger is building. The road from Nasiriyah to Baghdad is no longer safe at night. Robbers prowl the highway just as they slink through the streets of Baghdad. And I note an odd symmetry in all this. Under the hateful Taliban, you could drive across Afghanistan, day or night. Now you can't move after dark for fear of theft, killing or rape. Under the hateful Saddam, you could drive across most of Iraq without danger, day or night. Now you can't. American "liberation" has become synonymous with anarchy.

Then there's the confetti of daily newspapers appearing on the pavements of Baghdad which tell their readers of America's business earnings from this war. Iraq's airports are for auction, management of the port of Umm Qasr has been grabbed for $8.4m (£5m) by a US company, one of whose lobbyists just happens to have been President George Bush's deputy assistant when he was governor of Texas. Halliburton, Vice President Dick Cheney's old company, has major contracts to extinguish oil fires in Iraq, build US bases in Kuwait and transport British tanks. The most likely giant to hoover up the reconstruction contracts in Iraq is the Bechtel corporation whose senior vice president, retired general Jack Sheehan, serves on President Bush's defence policy board. This is the same Bechtel which - according to Iraq's pre-war arms submission to the UN, which Washington quickly censored - once helped Saddam build a plant for manufacturing ethylene, which can be used in the making of mustard gas. On the board of Bechtel sits former secretary of state George Schultz, who again just happens to be chairman of the advisory board of the Committee for the Liberation of Iraq which has, of course, close links to the White House. Iraqi reconstruction is likely to cost $100bn which - and this is the beauty of it - will be paid for by the Iraqis from their own future oil revenues, which in turn will benefit the US oil companies.

All this the Iraqis are well aware of. So when they see, as I do, the great American military convoys humming along Saddam's motorways south and west of Baghdad, what do they think? Do they reflect, for example, upon Tom Friedman's latest essay inThe New York Times, in which the columnist (blaming Saddam for poverty with no mention of 13 years of US-backed UN sanctions) announces: "The Best Thing About This Poverty: Iraqis are so beaten down that a vast majority clearly seem ready to give the Americans a chance to make this a better place."

I am awed by this and other "expert" comments from the US East Coast intelligentsia. Because it sounds to me, watching America's awesome control over this part of the world, its massive firepower, bases and personnel across Europe, the Balkans, Turkey, Jordan, Kuwait, Iraq, Afghanistan, Uzbekistan, Turkmenistan, Bahrain, Doha, Oman, Yemen and Israel, that this is not just about oil but about the projection of global power by a nation which really does have weapons of mass destruction. No wonder that soldier told me not to go out after dark. He was right. It's no longer safe. And it's going to get much worse.