Daesh-held cities and towns on both sides of the Syrian-Iraqi border have fallen like dominoes since Iraq announced the liberation of Mosul in July. Iraqi forces took nearby Tal Afar at the end of August, completing that battle in less than a fortnight. Clearing Daesh from Hawijah, its last urban stronghold in Iraq, took barely a day …

“I think Daesh will go from being a proto-state to an underground terrorist organisation with affiliates in different places in the world,” says Ali Soufan, a former FBI agent closely involved in investigating the 9/11 attacks, and author of Anatomy of Terror: From the Death of bin Laden to the Rise of the Islamic State, who now runs The Soufan Group. “But then there’s the ideological question: What’s going to happen if there’s no caliphate? They gave allegiance to a caliph and to a state that no longer exists …”