Ayatollah Abdelaziz al-Hakim told The Times that under US occupation and the interim administration the security forces had become infested with former officers of Saddam Hussein’s Sunni-led regime and needed to be shaken up. His comments are likely to worry Sunnis, who already fear that their grip on government is slipping.

“There are major infiltrations, varying in degree from the Mukhabarat (secret intelligence service) to Interior Ministry and to a lesser degree the Ministry of Defence. Some of them are semi-infiltrated,” he said. “Sometimes we come across their secret reports, where they use similar idioms and expression to those used in Saddam’s time, as if Saddam’s times were still here. This is sometimes painful, but sometimes it makes you laugh.”

One of his aides told The Times that intelligence officers were still asking Shia detainees who was behind the 1996 assassination attempt on Saddam’s son Uday, while others were asked who they had fought with in the Shia uprising of 1991.

The Ayatollah’s party, the Supreme Council for the Islamic Revolution in Iraq (Sciri), is the main player on a Shia list endorsed by Iraq’s leading cleric, Grand Ayatollah Ali al-Sistani, and including the former Pentagon darling Ahmed Chalabi and partisans of the rebel Shia cleric Moqtada al-Sadr.

With Grand Ayatollah al- Sistani’s blessing, the United Iraqi Alliance is expected to win at least 27 per cent of the seats in Iraq’s new parliament after the January 30 elections.

Ayatollah al-Hakim, poised to take power, already has the trappings of leadership in calamitous Baghdad. He was speaking in his heavily guarded headquarters — once the home of Tariq Aziz, Saddam’s Deputy Prime Minister — where he survived a suicide car bomb attempt on his life two weeks ago. Aides say that he has not left the compound since the attack. Dozens of armed men loiter in nearby streets, manning roadblocks that cause congestion in the neighbourhood.

Asked if he planned a sweeping purge of the intelligence and security forces that the Americans built up piecemeal after the war, the Ayatollah, who once commanded Sciri’s 10,000-strong militia, said: “For sure. If we want to improve the security situation. It’s natural and it’s one of our priorities.”

In their place, he said he would install “loyal Iraqis and the believers (in God), and those who believe in the process of change in Iraq”. His words caused alarm among Iraq’s liberal commentators.

“If he forms the government, that will be a disaster. He’ll purge the army, purge the police and put his own men in it,” said Ghassan al-Atiyyah, a secular Shia commentator, who is trying to build bridges with the Sunni community and defuse the uprising. “This is the road to civil war.”

Mr al-Atiyyah brushed aside the Ayatollah’s promise to ensure Sunni seats in government even if turnout was too low to bring their parties into parliament. “This is exactly what the old regime did,” he said.

Tawfiq al-Yasseri, the head of the parliamentary defence committee, said that a shake-up in the security apparatus was needed. “I agree completely with what Abdul Aziz said about the faults of the security system. They should be changed. All of them they are making dramatic mistakes.” He stopped short of endorsing a takeover by Sciri. “We need experienced people with clean hands who were persecuted by the former regime.”

Another commentator found it hard to believe that the Americans, having fought hard and long for elections, would allow an Iranian-backed Ayatollah to take control. “It will be doctored” to ensure pro-American secular moderates take the helm and write the country’s constitution, said the observer, who asked not to be named.

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