Dominic Raab has said he is “not confident with any precision” about how many people who are entitled to come to the UK remain trapped in Afghanistan.

Facing questions on the UK’s withdrawal by members of the Foreign Affairs Committee, the foreign secretary says his best estimate of the number of UK nationals and their family members, Afghans who might qualify for resettlement because they assisted the UK, and other vulnerable people who are yet to get out is in the “low hundreds”.

But Mr Raab was unable to give a more precise number when asked by Labour MP Chris Bryant “whether this is nearer 100 or 400”.

“Any number that we haven’t got out… is too many,” he told MPs on the committee, adding: “I can’t give you a definitive answer.”

And asked to confirm the prime minister’s assertion that the “overwhelming majority of people who worked for us are out”, the foreign secretary continued: “I’m not confident with precision to be able to give you a set number, but I am confident that the prime minister is right – that we’ve got the overwhelming number out.”

Mr Raab also confirmed he will be travelling to the region after the hearing concludes on Wednesday afternoon for talks about the rescue of those left behind in Kabul after the departure of the remaining foreign forces.

The foreign secretary, who faced criticism after it emerged he was on holiday in Crete while the Taliban was advancing on Kabul, refused multiple times to offer further details about when he went abroad.

Describing questions about his trip as a “fishing expedition” and “pretty partisan”, Mr Raab repeated that he “would not have gone away with the benefit of hindsight”.

He added: “I am not going to start adding to, frankly, the fishing expedition beyond the facts that I have articulated and the fulsome statement and having answered questions on this continuously.”

The foreign secretary also could not say how many of his department’s ministers are currently overseas.

He told MPs he did not have “the precise detail” to answer this question, but that there is “a rota system” in place to ensure cover.

“We’re always very careful about signalling travel movements because of the security implications,” he added.

Mr Raab maintained that he has remained fully engaged with the situation in Afghanistan, noting that he had “over 40 meetings or telephone calls where Afghanistan was on the agenda” between mid-March and 30 August – which works out as “broadly one every four days”.

He added that the “central assessment” of the UK government had been that Kabul was “unlikely” to fall this year.

“The central assessment that we were operating to – and it was certainly backed up by the JIC (Joint Intelligence Committee) and the military – is that the most likely, the central proposition, was that given the troop withdrawal by the end of August, you’d see a steady deterioration from that point and it was unlikely Kabul would fall this year,” he said.

The foreign secretary noted that this assessment remained “until late”, but that work to develop an evacuation plan was ongoing from June.

“We started planning in June for the contingency of an evacuation and therefore a full drawdown of the embassy,” he told the committee.

Asked by Conservative MP Bob Seely whether the government was caught out “slightly on the hop” due to an “intelligence failure”, the foreign secretary replied: “We’ve got a very professional way of approaching these things but when they’re wrong… you need to look at how you correct that.”

The foreign secretary also outlined the three categories of people in Afghanistan who are eligible to resettle in the UK as British nationals, those who have shown loyalty to the UK and an “asylum-related” group “based on international law”.

He repeated that the government is “doing everything we can” to get people out of the country, adding that “the proof” of this is that 17,000 people have been transported to the UK “since April”.