Boris Johnson will chair a third Cobra meeting over the situation in Afghanistan as Downing Street pledged to continue to evacuate people from the country for as long as it is safe to do so.
The Tory Prime Minister will hold the meeting this afternoon as a struggle to get UK nationals and local allies out of the country continues.
Johnson' s spokesman said the UK will continue the evacuation effort for "as long as we are able to do so and as long as it is safe to do so".
However, Defence Secretary Ben Wallace, who served in the Scots Guards, appeared to choke up as he spoke of his regret that "some people won't get back".
On LBC, Wallace said: "It's a really deep part of regret for me... look, some people won't get back. Some people won't get back and we will have to do our best in third countries to process those people."
Asked why he felt the situation "so personally", Mr Wallace replied: "Because I'm a soldier... because it's sad and the West has done what it's done, we have to do our very best to get people out and stand by our obligations and 20 years of sacrifice is what it is."
British troops are racing against the clock to get people out of Afghanistan following the dramatic fall of the Western-backed government amid a rapid advance across the country by the Taliban.
The Prime Minister's official spokesman said on earlier today there would be "significant numbers flying out day by day" and although he could not put a number on how many British citizens were still in the country, he added: "We have reinforced our capabilities with 600 military personnel who are there to facilitate the removal of people with UK visas and British nationals."
He said the British ambassador, Sir Laurie Bristow, was working from the airport in Kabul alongside Home Office staff, diplomatic workers, and the armed services, to process visas.
And he said: "There are people on the ground who can consider visa applications and there are some rules as regards to those who have family members who can be considered, I think, on a case-by-case basis but we have already removed a large number of Afghan nationals under the ARAP (Afghan Relocations and Assistance Policy) scheme and we'll continue to do so."
The spokesman said the ARAP scheme was "open-ended".
He told a Westminster briefing: "We will continue to do everything we can, our offer is open-ended, we haven't put an end date on that and we will continue to do all we can including - as the Defence Secretary said - should individuals manage to get to other countries and be brought in from those other countries."
He said it was a "fluid situation" but that military personnel were ensuring "people can leave safely at the moment".
He said: "We want to obviously continue to do this as long as we are able to do so and as long as it is safe to do so. You'll appreciate the US have said that they will be leaving at the end of the month so we will keep that under review and we'll continue to do it as long as we can do so because we want to get as many people out as we can."
Labour leader Sir Keir Starmer said there was an "obligation" to those in Afghanistan who had helped the UK effort.
Speaking on a trip to Wolverhampton, he said: "We need to get UK nationals out, but we also have an obligation to all of those Afghans who helped and assisted the UK, and we shouldn't have nice distinctions between this type of person, this type of help, and that type of help.
"If those in Afghan have helped us, the UK, in our work in Afghanistan, we have got an obligation to them."
He said in the longer and medium-term there needs to be "safe and legal routes for refugees".
And he added: "I think there was a catastrophic miscalculation of, on the one hand, the strength of the Taliban and the resilience of the Afghan forces.
"And I think anybody looking at this would say the timing of this decision to withdraw - nobody wants troops in Afghanistan indefinitely - but the timing of this withdrawal and what has happened and the unravelling of 20 years of progress in a matter of weeks and days, I think everybody is saddened by that and can see the tragedy that lies behind this."
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