The Prime Minister has denied that the sacrifices made by British forces in Afghanistan had been in vain.
"I don’t think that it was in vain. If you look back at what has happened over the last 20 years there was a massive effort to deal with a particular problem that everybody will remember after 9/11," Boris Johnson said.
"That was successful. To a very large extent the threat from al-Qaeda on the streets of our capital, around the UK, around the whole of the West was greatly, greatly reduced.
"I believe it was right, it was worth it and what we must do now is not turn our backs on Afghanistan."
Mr Johnson said the UK will use the methods at its disposal to try to ensure Afghanistan did not again become a base for international terrorism.
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"I think anybody in government in Kabul is going to recognise that the West, the UK, have a permanent interest in making sure that that does not happen," he said.
"We are going to use our diplomatic, our political, our overseas development aid budget to make sure we exert what pressure we can.
"But I think the idea of a military or a combat solution is not one that we would be pursuing right now."
He also said that it is not "realistic" to expect outside powers to impose a "combat solution" on Afghanistan.
"There isn’t a military solution. Thanks to the efforts of the UK armed services and all the sacrifices they made we have seen no al-Qaeda attacks against the West for a very long time," he said.
"I think we have got to be realistic about the power of the UK or any power to impose a military solution – a combat solution – in Afghanistan.
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"What we certainly can do is work with all our partners in the region around the world who share an interest with us in preventing Afghanistan once again becoming a breeding ground for terror.
"It is very difficult obviously, but I think the UK can be extremely proud of what has been done in Afghanistan over the last 20 years," he said.
Following a meeting of the Government’s Cobra contingencies committee, the Prime Minister said the "vast bulk" of the remaining British embassy staff in Kabul would return to the UK.
At the same time, he said that a team of Home Office officials was being sent to step up efforts to relocate Afghans who worked for the British forces in the country.
Cover image: Prime Minister Boris Johnson reflecting on the UK's withdrawal from Afghanistan (Picture: UK Parliament).