Sir Laurie Bristow, the British ambassador to Afghanistan has arrived in the UK, with the last British soldiers to leave Kabul expected to touch down within hours.
The final flight left on Saturday, bringing to an end the UK’s 20-year military involvement in Afghanistan.
More than 15,000 people have been evacuated by the UK since 14 August.
Vice Adm Sir Ben Key, who ran the UK’s evacuation, said he would be “very nervous” in saying the withdrawal was a success until all the allies had left.
He said it had been a “tremendous international effort” but it wasn’t “a moment of celebration for us at all”, adding that there was a “sense of sadness” at those left behind.
Prime Minister Boris Johnson said the UK’s departure was “the culmination of a mission unlike anything we’ve seen in our lifetimes”.
Ambassador Sir Laurie Bristow, who had been processing those fleeing the country at the airport, was among those who landed at RAF Brize Norton base in Oxfordshire on Sunday morning.
The flight came via the United Arab Emirates and further flights carrying military and civilian personnel are expected later.
Vice Adm Key, chief of joint operations, said that while he “pays testament” to everything achieved by British forces over the last two weeks, “we know that there are some really sad stories of people who have desperately tried to leave that – no matter how hard our efforts – we have been unsuccessful in evacuating”.
Speaking at RAF Brize Norton, he said the 31 August deadline imposed by the Taliban prevented them evacuating more people “who had helped us so wonderfully and courageously over the last 20 years”.
Photos of exhausted UK service personnel in aircraft coming back from Kabul showed how “deeply tired” they were having “given their all over the last two weeks”, he said.
“Some of the pictures that have come back in the last few days have painted a really good impression of just how desperate and difficult those conditions have been in the last few weeks.
“They have been sleeping in rough conditions, eating off ration packs and their sole motivation has been to help as many of the Afghans and British entitled personnel as they possibly could.”
He added that he had the most “enormous admiration” for what they have done.
There was no ceremony, no speeches. The diplomats and their colleagues walked off into the terminal building.
A few minutes later members of the 16 Air Assault Brigade – who had been at Kabul airport – walked quietly off the same plane.
The mission may be over – but it’s not complete.
A senior naval officer told me of his great sadness that local Afghan allies have been left behind. Their safety is now in the hands of the Taliban.