Thousands of supporters of Muqtada al-Sadr, the powerful Iraqi cleric, defied army warnings to demonstrate against the government, highlighting simmering political unrest in Iraq.  Protesters packed in to Baghdad’s Tahrir Square and cheered as a spokesman for the Shia cleric issued a list of demands that included the sacking of the country’s top three leaders — the prime minister, president and the parliament speaker.  Haider al-Abadi, prime minister, faces intense pressure to follow through on promised reforms and pledges to crack down on state corruption.  A string of bomb attacks in Baghdad and other cities in recent weeks, which have killed more than 300 people, have exacerbated the grim mood.  Protests against the government began in 2015 but grew this year when Mr Sadr’s supporters took to the streets demanding an end to graft and a governance system based on ethnic, sectarian and party quotas. They stopped in June when Mr Sadr briefly left the country.