Khanaqin, Diyala province

Four years after the US and British troops invaded Iraq the country is drenched in blood and its people full of fear. Iraqis often have a look of half-suppressed panic in their eyes as they tell how violent death had touched them and their families again and again.

"I have fled twice in the past year," said Kassim Naji Salaman, a burly driver in dirty brown robes, as he stood beside his petrol tanker outside the town of Khanaqin in central Iraq this week-end. "I and my family used to live in Baghdad but we ran for our lives when my uncle and nephew were killed and we moved into a house in the village of Kanaan in Diyala." Mr Salaman hoped he and his family, all Sunni, would be safer in a Sunni district. But almost everywhere in Iraq is dangerous. "Militiamen kidnapped my brother Natik, who used to drive this tanker, and forced him into the boot of their car," he continued. "When they took him out they shot him in the head and left his body beside the road. I am frightened of going back to Kanaan where my family are refugees because the militiamen would kill me as well."

Iraqis expected their lives to get better when the US and Britain invaded with the intention of overthrowing Saddam Hussein exactly four years ago today. They were divided on whether they were being liberated or occupied but almost no Iraqis fought for the old regime in 2003. Even his own Sunni community knew that Saddam had inflicted almost a quarter of a century of hot and cold war on his own people. He had reduced the standard of living of Iraqis, owners of vast oil reserves, from a level close to Greece to that of Mali.

No sooner had Saddam Hussein fallen than Iraqis were left in no doubt that they had been occupied not liberated. The army and security services were dissolved. As an independent state Iraq ceased to exist. "The Americans want clients not allies in Iraq," lamented one Iraqi dissident who had long lobbied for the invasion in London and Washington. Guerrilla war against the US forces by the five million strong Sunni community erupted with extraordinary speed and ferocity. By the summer of 2003 whenever I went to the scene of a bomb attack or an ambush of US soldiers I would find jubilant Iraqis dancing for joy around the pools of drying blood on the road or the smoldering Humvee vehicles. For Iraqis every year has been worse than the last since 2003. In November and December last year alone some 5,000 civilians were murdered, often tortured to death, according to the UN. This toll compares to 3,000 killed in 30 years of conflict in Northern Ireland. Many Iraqis have voted with their feet, some two million fleeing--mostly to Syria and Jordan-- since President Bush and Tony ordered American and British troops across the Iraqi border four years ago today.

So dangerous is it to travel anywhere in Iraq outside Kurdistan that it is difficult for journalists to provide evidence of the slaughter-house the country has become without being killed themselves. Mr Blair and Mr Bush have long implied that the violence is confined to central Iraq. This lie should have been permanently nailed by the Baker-Hamilton report written by senior Republicans and Democrats which examined one day last summer when the US military had announced that there had been 93 attacks and discovered that the real figure was 1,100. In other words the violence was being understated by a factor of ten.

Diyala is one of the most violent provinces in Iraq. It used to be one of the richest with rich fruit orchards flourishing on the banks of the Diyala river before it joins the Tigris south of Baghdad. But its sectarian geography is lethal. Its population is a mixture of Sunni and Shia with a small Kurdish minority. For at least two years it has been convulsed by ever escalating violence.

It is impossible for a foreign journalist to travel to Diyala from Baghdad unless he or she is embedded with the US forces. I knew, having made the journey before, that it was possible to get to Khanaqin, in the Kurdish controlled north-east corner of Diyala by taking a road passing through Kurdish villages along the Iraqi side of the Iranian border.

We started in Arbil, the Kurdish capital, and drove through the mountains to Sulaimaniyah three hours to the east. The Patriotic Union of Kurdistan (PUK), the party of Iraqi President Jalal Talabani, arranged a guide who knew the road to take us on to Khanaqin the following morning. We drove out of the mountains through the Derbendikan tunnel and then followed the right bank of the Diyala river, swollen by torrential rain, until we got to the tumbledown town of Kalar. It is important here to turn right over a long bridge across the Diyala because the next town on the road, Jalawlah, is contested between Kurds and Arab Sunni. The road then goes in the direction of the Iranian border until it reaches Khanaqin which is under PUK control.

What would have happened to us if we had gone on to Jalawlah became clear when we met a tribal leader from the town called Ghassim Mohammed Shati. Asked about the state of security in Jalawlah he said: "The centre of the town is safe enough but my father and brother and aunt were murdered on the outskirts in March 2005."

Mr Shati, who was also a police captain, was looking for help from the mayor of Khanaqin, Mohammed Amin Hassan, Hussein who seemed unable to provide it. Surprisingly the tribal leader did not favor just shooting the insurgents who had killed his relatives. He said; "The only solution is to give employment to the police and army officers who were sacked and now support al Qaeda. If they get jobs they will stop."

Everybody agreed that the situation in Diyala was worse than ever. Col. Azad Issa Abdulrahman, the gloomy looking chief of police for Khanaqin, said that the provincial capital Baquba with a population of 250,000, though only 30 miles from Baghdad, and another large town called al Miqdadiyah were under the control of insurgents. "The government only controls a few of its own buildings," he admitted. The insurgents say they are setting up the Islamic emirate of Diyala.

Earlier this month the US, with much fanfare, sent 700 soldiers from the 5 battalion of the 20th infantry regiment to Diyala to restore government authority. It fought a ferocious battle with insurgents in which it lost two armoured 'Stryker' vehicles. But, as so often in Iraq, in the eyes of Iraqis the presence or absence of American forces does not make as much difference to who holds power locally as the US military command would like to believe. Supposedly they are supporting 20,000 Iraqi security forces, but earlier this year it was announced that 1,500 local police were to be fired for not opposing the insurgents. At one embarrassing moment US and Iraqi military commanders were claiming at a video-link press conference that they had a firm grip on the situation in Baquba when insurgents burst into the mayor's office, kidnapped him and blew it up. Power in Diyala is fragmented. As in the rest of Iraq it is difficult to know who is in charge. Often it is local political or military warlords whose allegiances are multiple. For instance the Fifth Division of the Iraqi army is in Diyala province but is largely Shia. It was Shia soldiers manning checkpoints or Shia Mehdi Army militiamen wearing military uniforms that Mr Salaman, the Sunni petrol tanker driver, was chiefly frightened of encountering.

Iraqis like him face terrifyingly numerous threats. Pointing out that he was now the sole bread earner for 18 women and children because so many of his male relatives had been killed Mr Salaman said despairingly: "I can't even visit the village where they live because soldiers or militia or just men in masks might kill me. I don't even know how to send them money" He said the problem was that the army and police were all on one side or other of the sectarian or ethnic divide. He did not expect things to get better.

The Iraqi government, whose ministers issue optimistic statements about the improving state of their country, when on visits to London or Washington carries surprisingly little weight outside the Green Zone in Baghdad. Often its interventions do nothing but harm. For instance the main source of employment in Khanaqin is the large border crossing from Iran at Monzariyah. Cross border traffic provided 1,000 jobs. But the government has closed the crossing point and the road that used to be crowded with trucks a few months ago is now empty.

Another sign of diminishing government control is that no rations have been delivered in Diyala for seven months. Some 60 per cent of Iraqis depend on cheap government subsidized rations. But these no longer arrive because those delivering them say it is too dangerous to do so. This is understandable enough since the drivers of trucks containing the rations are often deemed to be collaborators by insurgents and shot to death. In Mr Salamaan's village of Kanaan five men were burned to death for the crime of guarding two petrol stations.

A difficulty in explaining Iraq to the outside world is that since 2003 the US and British governments have togethor produced a series of spurious turning points. There was the capture of Saddam Hussein in December 2003, the supposed handback of Iraqi sovereignty in June 2004, the two elections and the new constitution in 2005 and--most recently_the military 'surge' into Baghdad. In all cases the benefits of these events were invented or exaggerated.

After Sunni fundamentalists blew up the golden-domed Shia al-Askari shrine in Samarra in February 2006 central Iraq was torn apart by sectarian fighting. Baghdad broke up into a dozen different hostile cities, Sunni and Shia, which fired mortars at each other. Government ministries, if controlled by different communities, fought each other. The Shia- controlled Interior Ministry kidnapped 150 people from Sunni-held Higher Education Ministry and killed many of them.

For a brief moment last November after the mid-term elections in the US and the Baker-Hamilton report it seemed that the US was going to be start negotiations with its myriad enemies in around Iraq. But in the event President Bush refused to admit failure. Some 21,500 troop reinforcements are being sent to Baghdad and Anbar province to the west.

So far there is little sign that the 'surge' will really change the course of the war in Iraq. For the moment the Shia militias have stood down but Sunni bombings continue. "The Shia have stopped killing Sunni but the Sunni have not stopped killing Shia,' one government official told me. "If this goes on and the Sunni political leadership do not denounce them there will be an explosion of sectarian hatred even worse then before."

Diyala, its once prosperous fruit-growing villages now becoming heavily armed Sunni or Shia fortresses, is a symbol of the failure of the occupation that began four years ago. From an early moment it was evident that only the Kurds in Iraq fully supported the US and British presence. The Sunni were always going to fight it and the Shia would only play along with it so long as it served their interests. The biggest political change in the last year is that a majority of the Shia now support armed attacks on US-led forces.

The invasion four years ago failed. It overthrew Saddam but did nothing more, It destabilized the Middle East. It tore apart Iraq. It was meant to show the world that the US was the world's only super power that could do what it wanted. In fact it demonstrated that the US was weaker than the world supposed. The longer the US refuses to admit failure the longer the war will go on.

-- Patrick Cockburn is the author of 'The Occupation: War, resistance and daily life in Iraq', a finalist for the National Book Critics' Circle Award for best non-fiction book of 2006.