Traumatised Yazidis and Christians say they can't live alongside Sunni Arab 'collaborators'
The Sunni community of Iraq, some six million strong, has suffered badly, with all its main cities in addition to Mosul being heavily damaged by war. There are still 500,000 Sunni IDPs in Kirkuk, who are being allowed to return to wholly Sunni centres but not to those where Shia also live.
In both Iraqi and Kurdish- controlled areas there are camps that are little better than "open prisons", says Ms Wille, where IDPs cannot come and go from the camp freely, receive visitors or even own a mobile phone. Enforced demographic change may be one motive for this, but there is also genuine, though probably exaggerated, fear of Isil 'sleeper cells' waiting to strike.