Nato’s political campaign in Afghanistan was a failure, the defence secretary has said, as he insisted the western alliance had not suffered a military defeat at the hands of the Taliban. Speaking to the Commons defence committee on Tuesday afternoon, Ben Wallace said Nato forces could have stayed on in the country, but a “rotten deal” struck by Donald Trump’s US government led to the Taliban’s triumphant return. It was “highly likely” that there would now be a renewed threat from al-Qaida from Afghanistan, Wallace said. But, he added: “For 20 years we were safer, so we can bank that. “I don’t think that we were defeated. Our resolve was found wanting, I would say, rather than defeated,” he said. “Nato were there to enable a political campaign and I think that is what failed. The military were there to put in place the security environment in order to try and deliver that. “When that is withdrawn, that is when you find out whether your political campaign has worked. What we discovered is it didn’t work. It was the western resolve and the western narrative or political foundations they had laid failed. There are a lot of searching questions there for all of us.” In August, Taliban fighters quickly overran Afghanistan, with the Afghan army collapsing almost without a fight and a Nato withdrawal quickly taking on the appearance of a rout. Wallace said intelligence assessments at the beginning of August showed the Taliban were advancing in the provinces and beginning to take large cities, but that it was the opinion of agencies that the Islamist group would be in control of Afghanistan by the end of 2021. Despite that, Wallace insisted, the initial aim of the invasion, to dismantle al-Qaida in the wake of the 9/11 suicide attacks, had been a success. “We bought counter-terrorism success for 20 years,” he said. “Al-Qaida did not mount … a terrorist attack on the United Kingdom or her allies from Afghanistan. For many soldiers that is very important.” He added: “I think it is highly likely that we will see a return to al-Qaida and an increasing threat coming from Afghanistan.” The chief of defence staff, Gen Sir Nick Carter, had also been expected before the committee, but pulled out at short notice. Mark Francois, a Conservative MP, said Carter’s failure to appear “has not gone down too well”.