Sir: The catastrophe brewing in Iraq must be prevented before it consumes the entire Muslim East. Setting aside sectarian differences, Iran, Saudi Arabia, Syria and Lebanon have to work closely together to stamp out ISIS from Iraq. It must not be forgotten that the wrong policy of supporting al Qaeda and its affiliated groups in Syria has brought the situation in Iraq to this end. The only compensation left is to hold the region from plunging into further chaos with a combined force of every nation there. W Din Sydney, Australia