"I asked him if he was planning to run in 2008 and he said, 'No, that would be too soon'," Mr Khadim, who now lives in London, said.

General Petraeus has a reputation in the US Army for being a man of great ambition. If he succeeds in reversing America's apparent failure in Iraq, he would be a natural candidate for the White House in the presidential election in 2012.

His able defence of the "surge" in US troop numbers in Iraq as a success before Congress this week has made him the best-known soldier in America. An articulate, intelligent and energetic man, he has always shown skill in managing the media.

But General Petraeus's open interest in the presidency may lead critics to suggest that his own political ambitions have influenced him in putting an optimistic gloss on the US military position in Iraq .

Mr Khadim was a senior adviser in the Iraqi Interior Ministry in 2004-05 when Iyad Allawi was prime minister.

"My office was in the Adnan Palace in the Green Zone, which was close to General Petraeus's office," Mr Khadim recalls. He had meetings with the general because the Interior Ministry was involved in vetting the loyalty of Iraqis recruited as army officers. Mr Khadim was critical of the general's choice of Iraqis to work with him.

For a soldier whose military abilities and experience are so lauded by the White House, General Petraeus has had a surprisingly controversial career in Iraq. His critics hold him at least partly responsible for three debacles: the capture of Mosul by the insurgents in 2004; the failure to train an effective Iraqi army and the theft of the entire Iraqi arms procurement budget in 2004-05.

General Petraeus went to Iraq during the invasion of 2003 as commander of the 101st Airborne Division and had not previously seen combat. He first became prominent when the 101st was based in Mosul, in northern Iraq, where he pursued a more conciliatory line toward former Baathists and Iraqi army officers than the stated US policy.

His efforts were deemed successful. When the 101st left in February 2004, it had lost only 60 troops in combat and accidents. General Petraeus had built up the local police by recruiting officers who had previously worked for Saddam Hussein's security apparatus.

Although Mosul remained quiet for some months after, the US suffered one of its worse setbacks of the war in November 2004 when insurgents captured most of the city. The 7,000 police recruited by General Petraeus either changed sides or went home. Thirty police stations were captured, 11,000 assault rifles were lost and $41m (£20m) worth of military equipment disappeared. Iraqi army units abandoned their bases.

The general's next job was to oversee the training of a new Iraqi army. As head of the Multinational Security Transition Command, General Petraeus claimed that his efforts were proving successful. In an article in The Washington Post in September 2004, he wrote: "Training is on track and increasing in capacity. Infrastructure is being repaired. Command and control structures and institutions are being re-established." This optimism turned out be misleading; three years later the Iraqi army is notoriously ineffective and corrupt.

General Petraeus was in charge of the Security Transition Command at the time that the Iraqi procurement budget of $1.2bn was stolen. "It is possibly one of the largest thefts in history," Iraq's Finance Minister, Ali Allawi, said. "Huge amounts of money disappeared. In return we got nothing but scraps of metal."

Mr Khadim is sceptical that the "surge" is working. Commenting on the US military alliance with the Sunni tribes in Anbar province, he said: "They will take your money, but when the money runs out they will change sides again."