After three chaotic sessions mired in defence stalling tactics the stuttering case exploded into life with the first eyewitness account of the alleged round-up and massacre of 148 Shias in Dujail in 1982 for which Saddam and seven senior Baathists are accused of murder.

Ahmed Hassan Mohammed, then 15, told how the Baathist regime rounded up hundreds of Shia villagers after a failed assassination attempt on Saddam, killing victims with a human meat grinder and subjecting others — including pregnant women — to physical or mental torture.

Mr Mohammed, a member of the Shia Dawa party banned by Saddam, delivered a powerful but rambling tirade through a fusillade of interruptions from the defendants, including the pinstriped Saddam, who once again sought to stamp his authority on the hearing.

Holding up a glass-framed picture of his 14-year-old brother — one of seven killed by the regime — Mr Mohammed had a heated exchange with Saddam’s half-brother, Barzan Ibrahim al-Tikriti, telling him: “You killed a 14-year-old boy.”

“To hell,” shouted back Barzan from the dock. “You and your children go to hell,” replied the witness.

Weeping at times, Mr Mohammed told the Baghdad court that more than 500 men, women and children were rounded up by troops led by Barzan — who wore red cowboy boots, blue jeans and held a sniper rifle. They were first taken to al-Hakimiya intelligence headquarters in Baghdad and tortured for 70 days, then moved to Abu Ghraib prison. There, he said, he witnessed the grisliest sight.

“I swear by God I walked by a room and on my left I saw a grinder with blood coming out of it and human hair underneath. One man was shot in the leg with two bullets. Some people were crippled because they had their arms and legs broken.”

He claimed that his brother had been tortured in front of his 77-year-old father as guards told them: “Why don’t you confess? You will be executed anyway.” Then he described the plight of women prisoners, telling the court: “One mother told the guards, ‘This baby is going to die, I need milk’. The guard said, ‘If he dies throw him from the window ’. Indeed, he did die, and they did throw him from the window.”

Other prisoners, he said, were forced into the boots of cars to be driven to desert killing sites, guards terrifying them with stories of people being buried alive.

Throughout the evidence and earlier legal argument the seven accused interjected, Saddam shouting that the court was “made in America” and Barzan asking, “Why don’t you just execute us and get this over with?” When Mr Mohammed was cross-examined, defence lawyers and the other defendants pressed him repeatedly on details, claiming that he had been coached to tell lies and had given an inconsistent and exaggerated account.

But when Saddam rose to cross-examine he took a different tack, resorting instead to rhetoric, portraying himself as a heroic nationalist, the patient “father” of all Iraqis — persistently calling the judge and witness his “sons” — and questioning Mr Mohammed’s mental health, as the witness stared at him with contempt.

After one of many clashes with Muhammad Rizkar Amin, the presiding judge, Saddam exclaimed: “I’m not afraid of being executed.”

Jawwad Abdul Aziz, 34, a second witness, told of the destruction of his family’s orchards, wells and houses by bulldozers three months after the assassination attempt.

He said three of his brothers vanished, their deaths emerging from Mukhabarat (secret police) files discovered only after the fall of the “exPresident”. “I am the current President,” shouted Saddam, who denies all charges.

The other defendants include Barzan , Taha Yassin Ramadan, the former Vice-President, Awad Hamed al-Bandar, the head of Saddam’s Revolutionary Court, and four Baath officials from Dujail.

Earlier, the proceedings were adjourned after a walkout by the defence legal team, prominent among them Ramsey Clark, the 77-year-old former US Attorney-General.

They challenged the legitimacy of a court set up by the US occupation authorities and attacked the court for failing to provide security for the defence lawyers, two of whom have already been murdered.

• Gunmen kidnapped Bernard Planche, a French engineer, at his house in Baghdad yesterday. He worked for Aaccess, a non-governmental organisation, at the Risafa water plant in the Iraqi capital. Neighbours said that M Planche screamed as he was seized by seven gunmen in two cars. Dominique de Villepin, the French Prime Minister, warned French citizens not to travel to Iraq.

  British officials reported no progress towards securing the release of Norman Kember, the British peace activist, and four others abducted last week.

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