The final UK evacuation flight purely for Afghan nationals has left Kabul airport, ending an often chaotic process in which about 14,000 people were airlifted out of Afghanistan by British forces in less than two weeks, the Ministry of Defence has confirmed.

Any further flights to leave Kabul under the UK’s evacuation operation will also have UK diplomatic and military personnel onboard. It is thought any further flights would be able to transport those still needing evacuation, but would now also include personnel travelling back to the UK.

The British ambassador to Afghanistan, Sir Laurie Bristow, said it was “time to close this phase” of the evacuation effort.

In a video posted on Twitter, Bristow – who has remained in Afghanistan processing those who need to leave the country – said: “The team here have been working until the very last moment to evacuate British nationals, Afghans and others at risk.

“Since the 13th of August, we’ve brought nearly 15,000 people to safety, and about 1,000 military, diplomatic, civilian personnel have worked on Operation Pitting in Kabul; many, many more elsewhere.

“Thursday’s terrorist attack was a reminder of the difficult and dangerous conditions in which Operation Pitting has been done. And sadly I attended here yesterday the ceremony to pay our respects to the 13 US soldiers who died.”

Prompted by the US decision to remove all its forces from the country by 31 August, after 20 years, and hastened by the Taliban’s takeover of Afghanistan, the evacuation was punctuated by a bomb and gun attack on Thursday against people waiting at the airport and US troops, which killed more than 90 people.

While about 10,000 Afghan nationals who had worked with UK forces or other organisations have been removed under the Afghan relocations and assistance policy (Arap) scheme, up to 1,100 eligible people were left behind, according to the defence secretary, Ben Wallace.