Meanwhile, the Pentagon warned ISIS could launch foreign atrocities from the country in six months. Mr Wallace told the Commons defence select committee: “If the Taliban do not improve things for the people of Afghanistan, the likes of ISKP (Islamic State – Khorasan Province) will strengthen. They’re currently not in a position to mount attacks out of Afghanistan. That may well change.”

       The Pentagon’s under-secretary for policy, Colin Kahl, yesterday told US lawmakers that ISIS could develop the capability to carry out external attacks in six to 12 months.

       He described ISKP – an off-shoot of ISIS – and the Taliban as “mortal enemies”. He added: “The intelligence community currently assesses that both ISKP and Al-Qaeda have the intent to conduct external operations, including against the United States, but neither currently has the capability to do so.

       “We could see ISKP generate that capability in somewhere between six or 12 months.” Al-Qaeda could take “a year or two”.

       Meanwhile, asked about medals for UK troops who aided the withdrawal from Afghanistan, Mr Wallace said: “It is not a unilateral decision – there are committees on committees.”