British Prime Minister Boris Johnson has said the UK's diplomatic efforts to find a solution in Afghanistan remain ongoing, which leaves open the prospect of working with the Taliban if necessary.

Speaking to the media after an emergency Cabinet Office Briefing Rooms (COBRA) meeting to discuss the crisis in the region on Friday, Johnson said formidable challenges remain around the evacuation of British nationals and supporters from Kabul airport but the situation was getting slightly better.

"What I want to assure people is that our political and diplomatic efforts to find a solution for Afghanistan, working with the Taliban, of course, if necessary, will go on and our commitment to Afghanistan is lasting," Johnson said.

"The situation is getting slightly better and we are seeing a stabilisation at the airport. So yesterday [Thursday] we were able to get out about 1,000 people and today [Friday] another 1,000 people; a lot of those UK eligible persons coming back to this country and a lot of the people coming back under the Afghanistan Resettlement and Assistance Programme (ARAP) interpreters and others to whom we owe debts of gratitude and honour," he said, adding that the operation will continue at a fast pace.

"So the operation is becoming faster, but I'm not going to pretend that it's easy. The logistical challenges are formidable and they are doing an outstanding job in very difficult circumstances," he said.

Johnson also defended his Foreign Secretary, Dominic Raab, who has come under fire from the Opposition over a missed phone call with his Afghan counterpart in the now fallen Ashraf Ghani government at the peak of the crisis last weekend. He said he "absolutely" had full faith in the Cabinet minister, adding, "I can tell you that the whole of the government has been working virtually round the clock, hitting the phones, to do what we can to sort it out; to deal with a situation that has been long in gestation and to make sure that we get as many people back as possible."

Pressed on whether he believed suggestions from the new Taliban regime in charge that it may be more moderate in the future, Johnson said that it was important to take people at face value.

"We hope they mean what they say. But again, as I said in the House of Commons, and I think that this is the position of everybody from the President of the United States, President Macron of France, [German Chancellor] Angela Merkel, everybody that I talked to everybody is agreed that we will judge them on their actions, and that is the important thing," he said.

Since last Saturday, the UK says has evacuated 1,615 people, including 399 British nationals and their dependants, 320 embassy staff, and 402 Afghan nationals who worked for the UK government in Afghanistan.

Meanwhile, the government has announced 5 million pounds for local councils in England, Scotland and Wales offering to house Afghans who have arrived under the ARAP programme. Under the scheme, Afghans who face threats from the Taliban having worked for the UK in Afghanistan, have been allowed to come to Britain.