The delicate, grey-bearded figure of Iraq's exiled Ayatollah Mohammed Baqir al Hakim gingerly picked his way across the carpet before sitting cross-legged on the floor and greeting some of the most senior mullahs of the Islamic Republic of Iran.
As he nodded to those who hold the levers of power, the soft-spoken cleric whispered pleasantly to his neighbours, a smile of recognition flickering across his lips.
Friday prayers in Tehran are where the flame of the Islamic revolution still burns brightest, though yesterday it was but a flicker compared to the heady days of Ayatollah Khomeini's prayer rallies.
The vast carpeted hall was less than a third full, the audience stuffed with army and air force conscripts and officers ordered to attend as well as rows of senior government officials who owe their positions to their links with the ruling clergy.
Twenty years ago when the revolution still had fire in its belly, all the surrounding streets of the campus of the University of Tehran would have been packed with tens of thousands of people chanting "Death to America".
While Mr Hakim, a key ally for the West in the campaign to topple Saddam Hussein, took time out from running the main armed Iraqi Shia Muslim opposition group, the prayer leaders warmed to some well-worn themes of their middle-aged revolution.
"America only wants genocide in the region" said one of Tehran's most powerful hard-line clerics, Ayatollah Mohammed Yazdi. Mr Yazdi is a member of the Iranian regime's Council of Guardians, or as George Bush would say,on the main board of the "axis of evil" of terrorism.
Mr Yazdi's function on the council is to veto laws passed by the country's democratically elected parliament that ruling clerics deem unsuitable.
He delivered a public broadside against the reform-minded parliament yesterday to chants of: "Those who have Western values should be executed" and "death to the atheists". By the time Mr Hakim had taken his seat, Mr Yazdi was getting into his stride, sketching out the prospect of a war which would leave Iran encircled by the "Great Satan" – Afghanistan on one side and Iraq on the other.
"America is looking for oil and gas and is trying its best to break the spinal cord of Islam" said Mr Yazdi, triggering chants from the audience of "down with America, down with America".
Mr Hakim, in the front row, listened politely to the chants. Iran's military – whose officers dutifully chanted on cue –wants nothing more than to see Iraq's armed forces pulverised under the might of America's military machine.
And Iran's ruling clergy want to see the back of President Saddam, whose secular regime, brutal army and chemical weapons brought death to so many followers of the Islamic revolution.
But what Iran's ruling clergy fear is the emergence in Iraq of a resurgent, secular, oil-rich client state of America on their doorstep. That's where Mr Hakim, leader of the Supreme Council for the Islamic Resistance in Iraq, (SCIRI) comes in.
With up to 15,000 men under arms near the border, a militia among the Shiite Iraqi tribes and a guerrilla army of "tens of thousands" operating underground in Iraq, Mr Hakim may be Iran's strongest card in the conflict.
Long committed to an Iranian-style revolution in Iraq, Mr Hakim has performed a U-turn in recent months and now espouses an elected government, the precise form of which would be left to the Iraqi people to decide.
With more than 60 per cent of Iraqis belonging to the Shia faith, Mr Hakim and his Iranian sponsors are confident that they will be major players in that government.
On Thursday, surrounded by Iraqi armed guards, Mr Hakim spoke of his confidence that President Saddam will soon be gone.
"We think the regime will collapse quickly," he said. After an interim period of a year, a government would be formed bringing together all strands of Iraqi society, Sunni and Shia as well as Christian.
Mr Hakim favours US plans to attack President Saddam, despite opposing them a few months ago.
"We are going to use any chance we have to get rid of the regime. Saddam Hussein represents evil in its complete meaning and it is my responsibility to remove the nightmare," he said. He stops short of the prospect of the US military staying behind to run Iraq. He said Washington told him it had no such plans.
The US, training 9,000 Iraqi battlefield advisers to act as scouts, guides and interpreters for its forces, has been in close contact with Mr Hakim's London envoys. So far no training or other operations have taken place and Mr Hakim is not expecting to be armed by the US.
With the Iranian regime solidly behind him and the mullahs relishing the chance of thwarting the "Great Satan", Mr Hakim can look forward to marching back to into Iraq with the phrase "death to America" ringing in his ears.
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies