Iraqi Shia Islamist parties have reached a “preliminary agreement” to run a single list of candidates in parliamentary elections scheduled for January, with help from representatives of the most powerful cleric in Iraq, Grand Ayatollah Ali al-Sistani, Shia political figures said on Thursday.

If the plan works, and obtains Mr Sistani's explicit blessing, it could pave the way for an Iraq dominated by conservative Shia religious leaders for the first time since 1920. Shia Arabs make up 60 per cent of Iraq's population, and by far the largest number are followers of Mr Sistani.