Opposition: The bitter world of Iraq's Ayatollah-in-waiting

In the race to occupy the seat of power in Baghdad, few would put their money on the wraith-like figure of 63-year old Ayatollah Muhammad Bakr al-Hakim.

But as the US military's plans to invade Northern Iraq from Turkey face more difficulties, his 30,000-strong battle-hardened Badr Brigade militia is expected to play an increasingly important role in the coming war. As head of Iraq's largest opposition group, Ayatollah al-Hakim never tires of warning the United States that its military presence in post-war Iraq will not be welcome, and any attempt to install a Pentagon general to rule Baghdad may be met with a "religious war".

From his headquarters in Tehran he makes clear there is no place for even a temporary US military government in Baghdad, along the lines of General Douglas MacArthur's in post-war Japan. "Iraqi opposition forces can form a democracy," Ayatollah al-Hakim says. "But if the United States installs an American general, this is against the idea of democracy." Any attempt to establish a long-term American occupation of Iraq would set the Middle East ablaze, he says.

At Friday prayers, Ayatollah al-Hakim sat in the VIP area surrounded by the most conservative members of Iran's ruling elite. Amid chants of "Death to America" and "God is Great" the exiled cleric touches his forehead to a piece of sacred earth taken from his birthplace, the holy Iraqi city of Najaf.

Ayatollah al-Hakim, the leader of the Supreme Council for Islamic Revolution in Iraq (SCIRI), is among the highest-ranking Shia clergymen who wears the black turban of a sayyid, indicating he is a direct descendent of the Prophet. He is also the commander-in-chief of a formidable fighting force which is expected to move on Iraq from its bases in Iran as soon as the US-led war begins.

For 20 years Ayatollah al-Hakim's militia has been conducting a guerrilla war against Saddam Hussein's regime. In 1991 they came pouring over the border from Iran when President George Bush Snr urged Iraqis to topple Saddam while his forces were on the run at the end of the Gulf War. Soon posters of the cleric and the late Iranian leader Ayatollah Ruhollah Khomeini were appearing on walls in Basra, the epicentre of the revolt against Saddam.

The prospect of an Islamic revolution in Iraq terrified manySunni muslims, Kurds, Christians and secular Iraqis. Fears the uprising was being orchestrated from Iran was deeply destabilising for the US and its allies who feared militant Islam far more than Saddam Hussein, the man they had secretly armed for his war against Iran for more than a decade. Now his followers, numbering about 30,000 and heavily armed courtesy of Iran's Revolutionary Guards, are poised to begin their own offensive against Iraqi forces once the opportunity presents itself. Up to 1,000 SCIRI forces are reported to already be inside Iraq and the Ayatollah is confident tens of thousands of supporters will rise up inside Iraq once a US led war begins.

Armed Iraqis stand guard outside Ayatollah al-Hakim's headquarters. Inside the main reception room hang the portraits of the numerous close relatives tortured and murdered by Saddam's regime. The SCIRI leaderhas spent many years in prison in Iraq and has been tortured. He has survived seven assassination attempts. Among the 50 relatives killed by Saddam's security services were five of his brothers and nine nephews.

In 1980 Iraq's most senior cleric Muhammad Baqir al-Sadr and his sister were arrested. She was raped and murdered and he was killed with nails hammered into his head. The Ayatollah fled to Tehran and founded the Badr Brigade militia which fought in numerous battles after Saddam invaded Iran later that year. In 1995 it delivered a punishing blow to Saddam's 426th Brigade, killing several hundred men in the marshes that straddle the border between Iran and southern Iraq.

The Badr Brigade has bases across the Iranian province of Khuzestan where they are kept firmly out of public view. Ayatollah al-Hakim says the size and strength of his forces are a military secret. Despite his closeness to the conservative Iranian regime, Hakim has carefully nurtured links with the Bush Administration and is a fully signed up member of the official Iraqi opposition. Last week his brother Abdul-Aziz Hakim was elected to the leadership of the Iraqi exiles group which met in Arbil under the watchful and approving eye of US diplomats.

Ayatollah al-Hakim is eagerly awaiting his return home and the toppling of Saddam Hussein by a combination of US attacks and popular uprising. What role awaits him in the new Iraq will be one of Washington's greatest concerns in the coming months.