Iran’s fundamentalist politicians have cautiously welcomed the victory of Barack Obama, with Mahmoud Ahmadi-Nejad, the president, writing the first letter of congratulations to a US president-elect since the 1979 Islamic revolution.

But the victory of a Democrat calling for change in the US has generated its own set of concerns for Iran’s rulers. Most alarmingly, it could undermine the appeal and the legitimacy of the radical message they espouse.