The three top officials, whose departments are overseeing the evacuation, have spent the week on leave, the Times reported on Friday.

The civil servants in question are Philip Burton, Permanent Under-Secretary at the Foreign, Commonwealth & Development Office; Matthew Rycroft, Permanent Secretary at the Home Office; and David Williams, Permanent Secretary at the Ministry of Defence.

The news comes as the Labour Party is calling for Foreign Secretary Raab to step down after he had failed to call his Afghan counterpart in order to arrange the evacuation of UK diplomatic personnel and allied Afghans from Kabul. The top diplomat was apparently unavailable as he was holidaying on the Greek island of Crete – and reportedly delegated the call to Zac Goldsmith, the junior minister on duty.

However, no such call was ultimately made since. A Foreign Office spokesperson told British media that was due to the “rapidly changing situation” on the ground, though The Daily Mail reported that the Afghan Foreign Ministry refused to set up a call with the junior minister after Raab declined to handle it himself.

The Times reported that a group of ten Foreign Office and Border Force staffers tasked with processing visa applications had landed in Kabul on Tuesday night, two days after the Afghan capital fell to the Taliban militants with little to no resistance.

The paper quoted a government source as saying that “hundreds” could have been airlifted sooner if the team had arrived earlier, and that there were empty seats on planes leaving Kabul.

James Heappey, the Armed Forces minister, told Times Radio he did not believe any one phone call would have made a difference to the events on the ground, with the Taliban quickly closing in on Kabul.

Nevertheless, Labour leader Keir Starmer heavily criticised the government’s handling of the evacuation process in parliament this week. He took shots at Raab, saying that one “cannot coordinate an international response from the beach”.

Raab released a statement on Friday saying that media reports were “inaccurate.” He defended the government as having been “working tirelessly over the last week to help as many people evacuate from Afghanistan as possible.”

The diplomat said that on August 13, two days before Kabul was overrun by the Taliban, he was advised to call the Afghan foreign minister, but “this was quickly overtaken by events.”

“The call was delegated to a Minister of State because I was prioritising security and capacity at the airport on the direct advice of the Director and the Director General overseeing the crisis response,” Raab explained, adding that his Afghan counterpart agreed to take the call, but was ultimately unable to do so.

Raab said that 204 people were evacuated by UK authorities the morning after Kabul fell, and 1,635 have been evacuated since then. He previously told reporters that “everyone was caught by surprise by the pace and the scale of the Taliban takeover.”

The UK, like several other Western countries, scrambled to fly their citizens and Afghan helpers out of Kabul, after the Taliban seized most of the country in little over a week. The sweeping assault was launched as Washington was still conducting its withdrawal of US forces, which was set to be complete by August 31.

The Taliban’s victory sent terrified Afghans to swarm the tarmac at the Hamid Karzai International Airport in the hopes of catching flights out of the country. The ensuing chaos made the organisation of flights more difficult, in one instance forcing a German military transport to take off with just seven evacuees on board.