As a loyal officer under Saddam Hussein, the Iraqi major never imagined that one day he would become an insurgent, but when Iraq fell five years ago he was left bitter, jobless and desperate to drive the invading forces out.

“I saw my country collapse right in front of my eyes,” said Abu Abdullah, who has since orchestrated countless attacks against the U.Sx military, spent time in the notorious Abu Ghraib detention centre and briefly joined forces with al-Qaeda.

Recalling the invasion, he told The Times: “I felt as though my freedom was being snatched from me. It was one of the darkest moments of my life.” In many ways Mr Abdullah’s story is the story of the insurgency in Iraq, where the changing allegiances of Sunni Arab fighters has dictated the pace of a conflict that has claimed tens of thousands of lives since 2003.

He, like many Sunni Arab officers and other Saddam supporters, resorted to guerrilla warfare to kill better-equipped U.S. soldiers but gradually found that his nationalistic resistance had fallen under the control of the militant Islamists of al-Qaeda.

Appalled at the cruelty of attacks sponsored by al-Qaeda, Abdullah switched sides recently and is cooperating, albeit reluctantly, with the U.S. military as part of a grassroots security drive that has spread across Iraq.

Five years ago, as Major Abdullah, he was holed up in the Iraqi city of al-Kut, south of Baghdad, listening to the sound of American combat aircraft dropping bombs on buildings and the thunder of invading tanks. “When the infantry entered al-Kut most of my soldiers stopped fighting. They realised that the U.S. Army was much more powerful than ours,” he said. “We pulled out and returned to Baghdad. All my soldiers vanished. It was over.”

Abdullah, a married father of one, drove his family to his parents’ house in Samarra, a predominantly Sunni Arab city north of the Iraqi capital, which eventually became a haven for al-Qaeda.

With the former army disbanded, he spent the next year at home defeated and with nothing to do – until he started meeting other former army officers at coffee shops in town.

“We started to discuss things and develop serious ideas. Eventually we agreed to form groups and start fighting,” Abdullah said in a late-night interview at a Baghdad hotel, dressed in a maroon and blue tracksuit.

They were well prepared to begin an insurgency because, three months before the invasion, Iraqi military commanders had instructed all soldiers and officers to receive specific training in street fighting. Recruiting young men locally from April 2004, he started a branch of al-Tawhid wal Jihad, one of four main Sunni Arab insurgent groups that ultimately combined to become al-Qaeda in Iraq.

They had an abundance of rockets, guns, ammunition and bomb-making material, thanks to the many old Iraqi army warehouses dotted around the country that had been abandoned.

“Our objective was clear: to remove the occupying forces. We did not launch attacks in urban areas, just the outskirts of towns and on the main highways,” Abdullah said, emphasising that his group also never targeted Iraqis.

They operated north of Baghdad up to the oil-rich city of Kirkuk, firing rockets at American bases, planting roadside bombs against military convoys and, on occasion, following up with an armed ambush.

The first mission that Abdullah planned, against a base in Tikrit, was a bit of a failure because he miscalculated the distance for a barrage of rockets to be fired. He became much more accurate over time.

“We had many successful operations,” he said, with a knowing smile when asked if he had killed any American soldiers. Abdullah says that he lost 26 fighters. Over a 10-month period his men carried out attacks twice a day. Using their superior knowledge of the terrain they would creep down dirt tracks and hide in farm houses. “The Americans would never know where we were coming from.” Sharing intelligence at meetings with other insurgency groups, he recalled how praise was heaped on any fighter who pulled off a complex mission.

“That was motivational. When you heard of someone else’s successes you wanted to go out and do something better,” said Abdullah, a tall, well-built man who used to be a boxer and is a martial arts expert.

The former officer’s attacking spree was halted when he was arrested by U.S. troops driving away from the scene of his biggest mission – blowing up five American vehicles with 12 roadside bombs as they travelled towards the once-restive city of Fallujah, west of Baghdad, in March 2005.

“The soldiers told us that they were going to execute us by pushing us out of their helicopter. I thought to myself that I was just defending my country and if you want to kill me then go ahead,” he said.

Thrown into Abu Ghraib, the U.S.-run detention center that become infamous after American soldiers were pictured humiliating Iraqi prisoners, Mr Abdullah said that he was kept in a box-like cell that measured a meter square.Forced to sit squashed up because of his large frame, he said that he was held in there for 29 days, allowed out for only four hours a day.

He also claimed that he was beaten and interrogated repeatedly. “In one of the worst moments, which I will never forget for as long as I live, I was handcuffed to a chair and a female soldier hit me across the head with a metal pipe. You might be able to see the scar,” he said, touching his hair-line. “I started to bleed and she hit me on the arm, breaking it. They left me for a week without medical attention. As I experienced all of this I kept thinking about two things: my son and my country. I felt really sad for my country.”

Abdullah, who said that he never admitted to any crime, spent three months in Abu Ghraib before being moved to Camp Buka, a larger detention centre in southern Iraq, where he said that conditions were much better.

After another six months he was released, but his time in captivity left him even more embittered towards the U.S. forces and he vowed to return to the resistance. “When I arrived back in Samarra I found that a lot of things had changed. My group had become part of al-Qaeda and was killing members of the Iraqi security forces and even civilians,” he said.

Most of the people he had fought with had fled to Syria, being replaced by hired guns who were working for an influx of new commanders, many of them foreign. Abdullah said that other Arab countries and Iran were helping to fund the operations.

Despite many misgivings, he rejoined the group at the end of 2005 but quickly regretted it. “I found out that my cousin had been killed because he had refused to join.” Mr Abdullah was also shown footage of two policemen being beheaded.

“I could not tolerate or accept how they were working, so in the end I fled to Syria. I felt quite disappointed with the way that the resistance had become.” After only a week Abdullah returned to Iraq and took his family to Baghdad, where he used his car to work as a taxi driver. Leaving al-Qaeda meant that his life was in constant danger. Twice gunmen tried to shoot him and he was forced to move house four times.

Still opposed to the U.S. military and increasingly against the Shia-led Government of Iraq, Mr Abdullah dreamt of starting up a fresh resistance. But in late 2007 he was approached by two uncles and a cousin who had joined a new security movement, which was established by Sunni Arab tribes who had turned against al-Qaeda in Anbar province, once the heart of the insurgency. The concept – arming local people and charging them with security for their neighbourhood – appealed to Abdullah even though the group’s members, which number at least 90,000, were under the payroll of the U.S. military.

“I started to feel that the Americans were better than the Iraqi Government at that moment. I still look at them as occupiers. My feelings towards them have not changed. But my main concern is to stop the Iraqi people’s suffering,” he said. Agreeing to help to set up branches of the so-called Awakening movement in Samarra and other towns north of Baghdad, Mr Abdullah attended his first meeting with the U.S. military just over a week ago – something that he had resisted for months.

“When American soldiers turn up I feel very sad for myself, my country and the fact that I have to sit down and deal with them. I feel like wolves are eating my flesh during the meeting,” he said.

Abdullah, however, believes that the largely Sunni Arab Awakening groups lack support from the Government, which has pledged to find all members jobs in the regular army or police or a civilian role.

Asked what would be the outcome if the government failed to create new employment opportunities, the former insurgent responded: “An uprising.” As for his future, Abdullah just wants security for his son, now 6, adding: “I am determined to raise him to be a fighter like me.”