Hopes that the unrest could trigger regime collapse, voiced openly in the US and Israel, appear premature. But any real or imagined weakening of the Iranian government’s grip could presage a dangerous escalation of regional tensions.

Predominantly Shia Muslim Iran’s efforts to project its power across the Middle East have earned it many enemies. Its expansionist policy gathered pace after the strategic cuffs came off at the end of the cold war, and accelerated following the British-American debacle in Iraq after 2003.

Iran is now a leading actor in post-Saddam Iraq, Syria and Lebanon. These perceived encroachments are a cause of great resentment, not only in Iraq’s Sunni heartlands to the north and west of Baghdad but especially in the headquarters of Sunni Islam, Saudi Arabia.