Robert Fisk on the motives behind the invasion of Mosul Syria’s army and Hezbollah and Iranian allies are preparing for a massive invasion by thousands of Isis fighters who will be driven out of Iraq when Mosul falls. The real purpose behind the much-trumpeted US-planned “liberation” of the Iraqi city, the Syrian military suspect, is to swamp Syria with the hordes of Isis fighters who will flee their Iraqi capital in favour of their “mini-capital” of Raqqa inside Syria itself.