Given the threat posed to this country’s security by returning jihadists, we have a role to play in this coalition against Isil, though Mr Cameron is right to rule out committing UK troops to the region. There is no public appetite for another long-term overseas military adventure. The terrorist group is not going to be defeated from the air and boots will be needed on the ground – but they need to be the boots of local forces, not of ours. Coalition air cover will give them a better chance to defeat Isil; but what happens after that must be for the Iraqis, Syrians, Kurds, Turks, Iranians and all the other regional players to decide.