The last dedicated evacuation flight back to the UK left Kabul overnight, Sky News understands.
Remaining flights over the weekend are set to bring home British troops as well as the final small numbers of Afghan evacuees who have permission to fly, defence sources said.
The UK ambassador in Kabul, Laurie Bristow, said in a video posted on social media that his team had been “working until the very last moment”.
Almost 15,000 people had been airlifted to safety, he added, tweeting that “our commitment to the people of Afghanistan will endure”.
Earlier, the chief of the defence staff, General Sir Nick Carter, said the final stages of the withdrawal and evacuation represented the “hardest” of any phase of war.
He added: “There has to be an ever diminishing rearguard that protects your back as you’re evacuating yourselves, and of course there comes a point when it really is the last aeroplane out.
“There are all sorts of things that can go wrong” when the final planes leave, such as the “threat of terrorism”, he said.