It will probably be a long time before the world again witnesses the downfall of a dictator, captured dramatically by the toppling of an imposing statue in the glare of TV cameras - as happened to Saddam Hussein's bronze image in Baghdad on April 9 2003.

But little did global viewers of this historic event imagine that the collapse of the ostensibly secular Saddam would be followed by rise - unseen - of Grand Ayatollah Ali al-Sistani, a reclusive 73-year-old Shia cleric based in the holy city of Najaf. For all practical purposes, Sistani is the single most important leader in Iraq today.

To add insult to injury, it has been established that the dramatic event of four years ago was far from a spontaneous action by the Iraqis celebrating their liberation from Saddam's tyranny by the benevolent troops of America and Britain.

It was stage managed. The jubilant crowd consisted mostly of the members of the Free Iraqi Force militia of Ahmad Chalabi's Iraq National Congress who had been ferried into Nasiriya a week earlier in US helicopters and then flown into Baghdad. The very convenient arrival of the US Marines along with a crane was part of the show as well.

Now, far more telling is the statement of Kadhim al-Jabouri, an Iraqi weightlifting champion who, in front of TV cameras, pounded through the concrete plinth bearing the statue.

"The devil you know is better than the devil you don't," he said, on the fourth anniversary of the US-led invasion. "We no longer know friend from foe. The situation is getting more dangerous. People are poor and the prices are going higher and higher ... Saddam was like Stalin. But the occupation is proving to be worse."

The prime occupying power, America, is allied with the government of Iraqi prime minister Nouri al-Maliki, a leader of al-Dawa al-Islamiya, a religious Shia party.

Al-Dawa is an integral part of the Iraq United Alliance (UIA), a coalition of religious Shia parties, conceived and blessed by Sistani.

Sistani does not dabble in day-to-day politics. He speaks through his aides only on the issues of prime importance. For instance, he disapproved of the wholesale privatisation of the 192 public sector companies that Paul Bremer, the US pro-consul in Baghdad, ordered in September 2003. He also declared that hydrocarbons belonged to the nation, thereby discouraging Bremer from seriously considering privatising the oil industry.

By calling for huge, peaceful demonstrations for direct elections to the transitional parliament charged with drafting the constitution in January 2004, Sistani squashed the American plans for a hand-picked body of Iraqis, guided by American experts, to draft the constitution along secular, democratic and capitalist lines.

When the US-appointed prime minister, Iyad Allawi, began dithering about holding elections to the interim parliament by January 2005, as stipulated by the UN Security Council Resolution 1546, Sistani informed UN secretary-general Kofi Annan that he would call for popular non-cooperation with the occupying forces if the promised poll did not take place.

Allawi yielded. In that election, the UIA won a majority of seats, and became the chief architect of the constitution. It stipulates that the Sharia law is the principal source of Iraqi legislation and that no law can be passed that violates the undisputed tenets of Islam.

Ibrahim Jaafari, a Dawa leader, became the first elected prime minister. Once the constitution was drafted and ratified in a referendum, there were elections to the 275-member parliament in December 2005. The UIA emerged as the dominant group, just 10 seats short of majority.

Though Jaafari won the contest for the UIA leadership by one vote, he was not acceptable as the prime minister to the Kurdish parties and to Washington and London. A crisis paralysed the government. It was Sistani's personal intercession that led Jaafari to step down, making way for Maliki.

In December 2006, when US officials urged Maliki to postpone Saddam's execution until after the religious holiday, it was to Sistani that Maliki turned for his religious opinion. Sistani reportedly gave his assent to an immediate execution.

Now, even when a major constituent of the UIA feels dissatisfied with the Mailiki government's action, its leaders dare not break away. They know that such a step would anger Sistani and lose them popular support among Shias.

The latest example of Sistani's unmatched power is his disapproval of the Washington-backed legislation to allow thousands of former Baath Party members to resume their government service. With that, this proposal is dead on arrival.

Little did US president George Bush realise in April 2003 that out of the ashes of Saddam Hussein would emerge an Islamist leader in the shape of a bearded and turbaned Sistani.