Shortly before his death last December, Grand Ayatollah Hossein Ali Montazeri, the opposition’s spiritual leader, excoriated the Basij. “Why do you beat people?” he demanded. “Because they do not accept what you say? Basij was founded to act within the path of God, not Satan. Isn’t it unfortunate to go to hell for the benefit of others?”

At opposition protests, the militiamen are taunted with the chant: “Cannon, tanks and Basijis no longer have an effect.”

The Basij’s fall from grace, in the eyes of many Iranians, began when the war with Iraq ended in 1988. Its members were given a new role as moral vigilantes fronting the drive against liberal tendencies at home – such as women flouting the official dress code.

Then, during the 1997 to 2005 reformist presidency of Mohammad Khatami they served as shock troops breaking up pro-reform gatherings and student protests.
The Basij’s power grew rapidly after Mr Ahmadinejad, a former Revolutionary Guard, was elected president in 2005.

Revolutionary Guard and Basij commanders ordered their foot soldiers to vote for him and he rewarded the affiliated forces generously, enmeshing them deeply in Iran’s political and economic structures.