The Prime Minister has praised UK military personnel that were deployed on Operation Pitting - the mission to evacuate people from Afghanistan.
Boris Johnson was speaking as 120 members of the Armed Forces involved in the evacuation mission paraded through Westminster to a parliamentary reception at the Palace of Westminster.
"I was impressed," he said in a speech.
"Although not just by your bravery, of course, and the way you dealt with so much – including the appalling terrorist attack that happened at Karzai airport.
"What really struck me talking to you was the professionalism, the care, with which you dealt with human beings in an extreme state of fear and distress and the diplomacy with which you worked with those Afghans, Taliban or otherwise."
Operation Pitting was carried out in August, with 15,000 people evacuated from Afghanistan as the Taliban claimed large parts of the country.
The mission also saw the biggest airlift in Royal Air Force history.
The Prime Minister continued: "That operation – Operation Pitting – will go down as one of the great achievements of our UK Armed Services in the whole of the post-war era.
"I believe that you stood for and you revealed the very best of the values of this country. And on behalf of all of us here today I want to say thank you, thank you very much."
Watch: PM thanks Armed Forces personnel deployed on Operation Pitting
The military personnel marched in procession from Wellington Barracks to New Palace Yard, before attending a reception in Westminster Hall. The parade was escorted by The Central Band of the RAF.
The reception was also attended by 30 guests representing the contribution of other Government departments and civilian authorities.
After the Op Pitting's completion, there was talk over whether those personnel involved should receive medals for their role.
The Ministry of Defence said the awarding of medals, which would go against the precedent of eligible operations lasting 30 days, would require "lengthy consideration".
The vast majority of voters in a Forces News poll believed personnel involved in Op Pitting deserved medals for their work.