Muqtada al-Sadr’s Marching Towards Reform alliance of reformed Shia militants and communists came first in four of the 10 provinces counted.

His Mahdi Army waged a brutal and costly insurgency against coalition troops during the 2006-2008 civil war and offered a reward for any British soldiers captured.

Mr Sadr has since disavowed violence against fellow Iraqis and in 2008 ordered his forces to become a humanitarian group.

Mr Sadr himself rebranded as a secular nationalist, campaigning against corruption and for reform, a message which seemed to resonate with Iraqis tired of entrenched sectarianism and graft.