Muqtada leads the only real mass movement in Iraq. It's a mass movement of the Shia, who are 60 percent of the population, and of poor Shia - and most Shia are poor. Otherwise the place is full of sort of self-declared leaders, many of whom spend most of their time outside Iraq.

I don't think the whole of Iraq would be under al-Sadr, but I think he would be the predominant force on the Shia side. Quite contrary to his sort of maverick, firebrand image, he's shown a propensity to deal with the other side, to look for compromises, to negotiate. You might have a loose federation [in Iraq].

Muqtada belongs to the most famous religious family in Iraq, which is the al-Sadr family. He's really the third in line. [Muqtada's father] drew his power from the first really important al-Sadr, Muhammad Baqir, who was executed by Saddam in 1980, together with his sister. So it's really a family of martyrs, and that's why Muqtada suddenly emerged from nowhere with the fall of Saddam.

Despite the fact that there's billions of dollars sitting in the Iraqi government reserves, somehow they are incapable of getting it out to the people. There are a very large number of people here who are on the edge of starvation. For those sort of people - a sizable chunk of people - that service makes them regard Muqtada as a sort of god.

There are some things that could hold it together, notably oil revenues. But at the moment, the much vaunted surge has had a measure of success primarily, to my mind, because Sunni and Shia Iraqis hate and fear each other more these days than they hate and fear the Americans.

There are sort of Kurdish districts there in Mosul, or there used to be, but the Kurds mostly fled or were driven out. The same is true of the Christians.

Muqtada is radical in the sense that he wants the U.S. occupation to end and has always said so from the beginning. Secondly, his support among the Shia really runs along class lines; it's mainly the poor who support him. His organization runs an enormous social network.