A further 200 British troops are being sent to Kabul, bringing the number of UK armed forces personnel in the city to around 900, the majority of which have been deployed in the past week.
It is understood several hundred further troops are also ready to be deployed if needed.
Foreign Secretary Dominic Raab said the world has been “surprised” by the speed with which the Taliban took control of the country.
He said:
“Everyone, I think, has been surprised by the scale and the pace at which the Taliban have taken over in Afghanistan.
“And that’s a lesson that we’ve all got to learn from. But the truth is what matters right now is focusing on getting British nationals out, getting out those who have so loyally served the UK.
“And making sure that the gains that we’ve made over 20 years are not lost.
“Let’s remember we haven’t had a terrorist attack on the UK from Afghanistan in 20 years.
“Because of UK aid, ten million more children have been in education. Because of UK efforts with others, eight million more landmines have been cleared.
“So we have a record that we should not overlook. Of course, the priority now is to make sure that the gains aren’t lost because of the Taliban taking control.”
The foreign secretary described the Taliban takeover of Afghanistan as a “new reality” although “not what we wanted”.
“We’re making it clear with our partners with all the means at our disposal, that we will hold the Taliban to account, to its commitments, to have a new start in Afghanistan.
“It’s clearly not going to be to the values that the UK, the west, the European Union, the Americans believe in, but we can have a moderating influence.
“I think it’s important we use all of the policy tools at our disposal – working with our partners – to try and achieve that.”
