It has always been fiendishly complicated to work out how Iran might act because there is no single Iran. That is true of its leaders as much as its people. An element of democracy is woven through the political fabric, and the elected president is the face of Iran that the world sees. However, there is no question but that the unelected clerics, backed by the armed forces, are ultimately in charge.

The top of the pyramid, at least, is entirely clear. Grand Ayatollah Ali Khamenei, 70, a hardliner who has actively manoeuvred against reform, promoted the nuclear programme and fostered ties with Hamas and Hezbollah, is the most powerful figure in Iran. His role has been described as “part pope, part commander-in-chief and one-man Supreme Court”. He is appointed (and could be deposed) by the Assembly of Experts, a group of 86 experts, mainly clerical, who are directly elected by the people every eight years. In theory this inserts democratic accountability even over the Supreme Leader; in practice, it has meant he is picked by conservative clerics.

Pictures of Khamenei are pasted across Iran. His support was thought crucial in securing Mahmoud Ahmadinejad’s victory in the 2005 presidential election, and Khamenei rushed to congratulate him again on winning this time. Khamenei calls the shots — perhaps literally, in the attempt to put down the uproar on the streets.

Next in power comes the Guardian Council, currently made up of conservatives close to Khamenei. He appoints six clerics to the council, and the judiciary (the head of which is also appointed by Khamenei) nominates six scholars in Islamic law, who are approved by parliament. The council choked off most of the presidential contest, deeming all but four would-be candidates ineligible, out of about 4,000 who wanted to run. Yesterday Khamenei announced that the council would hold an inquiry into allegations of election rigging, but this was seen widely as an attempt to buy time.

Khamenei also picks the head of the armed forces, who commands its two wings, the 125,000-strong Revolutionary Guard, and the 400,000-strong regular forces (more than half conscripted), plus 350,000 reservists.

One of the Supreme Leader’s most powerful supporting institutions is the Expediency Council. He appoints the members and they supervise all ministries. They have, in theory, the final say in any dispute between parliament and the Governing Council but in practice the Governing Council is likely to come out on top.

The president, described in the Constitution as the second-most-powerful figure, is in reality tightly circumscribed by the Supreme Leader and the tiers of bodies that answer to him. It is unlikely, for example, that Ahmadinejad could have pursued the nuclear programme with such aggressive vigour unless Khamenei backed him. But he did.

The same constraints — but even more pronounced — apply to the Majlis, frequently more liberal than the other institutions and significant in its influence. Its 290 members, elected every four years, have the power to initiate legislation and, in theory, to dismiss the president. However, because all of their Bills and other moves have to be approved by the Governing Council, they have much less freedom of manoeuvre than the Constitution might seem to imply. Apart from these institutions there are figures of enormous influence. Ali Larijani, Speaker of the parliament, was seen before the election as a potential rival to Ahmadinejad. A conservative, but seen as much more moderate than the President, he helped to bring an end to the crisis in 2007 over the detained British sailors. He was Iran’s chief negotiator until last summer but Ahmadinejad replaced him with someone who took a much more uncompromising approach. However, Larijani took Ahmadinejad’s side yesterday, attacking criticism of the election results from abroad.

Hojatoleslam Ali Akbar Hashemi Rafsanjani is a towering figure. A politician-cleric, former President, deputy chairman of the Assembly of Experts, chairman of the Expediency Council and businessman, he lost the 2005 election to Ahmadinejad and has been openly critical of him in this campaign. That is an extra factor that makes it hard for Ahmadinejad, and even Khamenei, to dismiss the uproar.

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