Dominic Raab has defended the Government’s handling of the Afghanistan crisis as he said the “rapidly deteriorating situation” in the country had prevented a call being made to Afghan ministers while he was on holiday.

The Foreign Secretary has come under increasing pressure to resign after it was revealed he was on the Greek island of Crete as the Taliban took control of Afghanistan.

But Mr Raab said ministers have been “working tirelessly” over the last week to evacuate British nationals and Afghans, with the priority being keeping Kabul airport open.

It came after it was reported that Foreign Office officials advised the Cabinet minister on August 13 to call Afghan foreign minister Hanif Atmar – two days before the Taliban marched on Kabul – to arrange help for those who supported British troops.

But Mr Raab delegated this to junior minister Lord Goldsmith, and it later emerged the call had never been made.

In a statement, Mr Raab said: “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.

“In any event, the Afghan foreign minister agreed to take the call, but was unable to because of the rapidly deteriorating situation.”

He went on: “The Government’s approach to prioritise security at the airport was the right one. As a result, 204 UK nationals and their families, Afghan staff and other countries citizens were evacuated on the morning of Monday 16 August.

“Since then, 1,635 have been evacuated. I pay tribute to the excellent team we have in place, and we continue to prioritise what is required to evacuate people to the UK safely.”

Mr Raab wrote on Twitter that his statement was “responding to the inaccurate media reporting over recent days”.

It comes as Boris Johnson called the latest in a series of COBR meeting on Friday afternoon over the crisis.

The Times reported that Sir Philip Barton, Matthew Rycroft and David Williams, the respective permanent secretaries of the Foreign Office, Home Office and Ministry of Defence, were on holiday amid the evacuations from Afghanistan.

It is understood the senior officials continued to work on Afghanistan while on leave, with the Whitehall departments running systems where there is another minister or an acting permanent secretary to cover periods of leave.

But Labour has demanded details about the Government’s handling of the situation in Afghanistan and the Foreign Secretary’s holiday while Kabul fell to the Taliban.

Former Cabinet minister David Davis said it was “nonsense” that Mr Raab should consider his position after he was found to be on holiday in Crete as Afghanistan fell to the Taliban.

Speaking to the PA news agency, he said that while there had clearly been failings in the handling of the crisis by the Government, they could not be directed at any one person and that having worked with Mr Raab he was a “workaholic” who would often pull 60-hour weeks.

Mr Davis said: “Last Friday, nobody in the House of Commons, or anywhere in Fleet Street or anywhere, or indeed, in the organisation of the Taliban knew that they would have, by Sunday, taken Kabul. Nobody.

“The Americans were saying it could happen in 30 days, our own intelligence said similar. So the idea that somebody should rush back from a holiday – frankly, a workaholic minister, which is what he is – is sort of daft, really, it’s worse than 20:20 hindsight.

“The Government’s not had a good week, let’s be clear about this, in terms of the handling of this crisis, and it looks like somebody is trying to scapegoat one member of Government.”

However, others felt there was still more to do to stabilise the situation.

One senior Tory MP said the Government needed to put in place a single contact for the evacuation effort.

Another reportedly told the Guardian Mr Raab’s position was untenable and that “not coming home was his biggest mistake”.

A third prominent Tory figure said the handling had been chaotic, but that the focus now needed to be on evacuating people from Afghanistan, with questions to be asked later.

Security minister James Heappey said the Taliban was being “officious rather than malicious” in stopping people reaching Kabul airport for evacuation flights.

A total of 963 people have been evacuated from Kabul on the RAF “air bridge” in the last 24 hours, according to the minister.

The former soldier, who fought in Afghanistan, added that he is kept “awake at night” by the knowledge the UK will not be able to get “absolutely everybody out”.

Mr Heappey said it is unclear how long the UK evacuation plan will last as it is dependent on the “dynamic” circumstances.

He said he understands that the Taliban is not turning people away from Kabul airport, noting: “Where they have done, I’ve heard it’s more that they are being officious rather than malicious.