Kabul evacuation: British and US forces at their most vulnerable as they prepare to finally leave Afghanistan

There are thought to be few surface-to-air weapons in Afghanistan and while rocket propelled grenades lack accuracy for attacking a moving plane, the terror threat from Isis could include heavy machine gun fire. “But there will be a lot of US fire power circling overhead capable of striking back if anyone does try to interfere with the withdrawal. It may make them think twice about doing it,” Mr Reynolds added.