ISK, the affiliate of the so-called Islamic State in Afghanistan, is a threat to the UK, a former military chief has warned.
Ex-joint forces Commander General Sir Richard Barrons told Times Radio the attack on Kabul airport showed the group was "a risk to the United Kingdom, here at home, and to our interests abroad."
The airport attack saw a number of Afghans two British adults and the child of a British national, killed.
The blast is believed to have been carried out by ISK
"We're going to find common cause with the US, and indeed I think the Taliban, in bearing down on this terrible organisation for as long as it takes to neuter them," Sir Richard said.
He added it was likely Britain will have to co-operate with the Taliban to prevent any terrorism coming to the UK and also to get any other Britons who have been left behind in Afghanistan back home.
"Before we arrived at this current catastrophic outcome, we had a diplomatic presence, we had a relationship with the Afghan intelligence organisations and we were able to work with some of the very good but now completely dissolved elements of the Afghan security architecture," he said.
"We also had the benefit of the sort of drone eyes-in-the-sky that the US provides. And now, all we have left is recourse to this over the horizon, drones support.
"So what this actually means is we're going to end up co-operating, not just with the US, but with the Taliban in the future in order to deal with Isis-K."
He added later: "We are going to have to be pragmatic, I think this will be quite a slow process, it will be conditional but it is necessary."
Echoing comments he previously made, he described the US decision to leave Afghanistan "on the basis of a date in the calendar" as a "failure of strategy".
More than 14,000 people have been lifted out of Afghanistan in the past two weeks and around 1,000 are being left behind.
