Speaking at a hearing of the powerful Liaison Committee - which has a membership made up of parliamentary select committee chairs - the PM was told by SNP MP Angus MacNeil that the "game is up".

Asked by Mr MacNeil if he would still be in place tomorrow, the PM replied: "Of course."

Politics Hub: Boris Johnson on the brink as resignations continue

Later asked by Labour's Darren Jones, chair of the Business, Energy and Industrial Strategy Committee, how his week is going, Mr Johnson replied: "Terrific."

Mr Jones told the prime minister "on a very human level, you must know that it's in the country's interest for you to leave".

The Labour MP said it was not "funny" for Mr Johnson to remain in power, telling the PM: "It is not a game."

But Mr Johnson repeated that he has a "duty" to continue on and that it would not be "responsible" for him to leave No 10, given the scale of the challenges facing the country.

"I look at the the pressures that people are under and the need for government to focus on that, on their priorities, which is what we are doing," he told members of the committee.

"I look at the biggest war in Europe for over 80 years and I can't for the life of me see how it is responsible just to walk away from that.

"As I said, earlier on, particularly not when you have a mandate of the kind that we won two, three years ago."

Mr Johnson insisted both the truth and accuracy of language are "very important" to him during a line of questioning by Conservative chairman of the Justice Committee Sir Bob Neill.

Meanwhile, William Wragg, a Tory MP who described the PM's position as "untenable" in January, asked Mr Johnson at "At which point does it become impossible for the Queen's government to be continued?"

Mr Johnson replied: "I really think you are underestimating the talent, energy and sheer ambition of Members of Parliament, and they want to get things done."

He added that governments cannot solve problems by "threatening to call elections".

PM to 'keep going'

At PMQs, the prime minister pledged to "keep going" in his role despite 27 MPs at that time having resigned from his government.

The number of resignations, which began after Number 10 admitted Mr Johnson had known about allegations of inappropriate behaviour by the MP Chris Pincher from 2019 before hiring him as deputy chief whip in February, have now risen to over 30.

Mr Pincher resigned from the role last week after further allegations that he groped two men at a private club in London, and he was later suspended from the Conservative Party.

Former senior civil servant Lord McDonald revealed on Tuesday that the PM had been told in person of the 2019 allegations, despite what Downing Street was telling the press.

At the Liaison Committee hearing, the PM once again refused to deny that he had said "Pincher by name, Pincher by nature" in reference to the disgraced MP's actions.

Less than 12 hours later, Rishi Sunak resigned as chancellor and Sajid Javid quit as health secretary, prompting a flurry of more junior ministers saying they could no longer support Mr Johnson.

An ally of the PM told Sky News Mr Johnson will fight to the end, not because he thinks it will turn things around, but because he wants it to look like he is being dragged from office.

Asked if the PM knows the end is coming, the ally appeared to suggest Mr Johnson does, adding "of course he does he's got eyes and ears".

1922 Committee could change confidence vote rules

However, it may not be up to Mr Johnson whether he is allowed to continue as prime minister, as the executive of the 1922 Committee of backbench Tory MPs is expected to meet in at 4pm to discuss potential rule changes - which could lead to another confidence vote in their leader.

Under current rules, the prime minister is now immune from another leadership challenge for 12 months.

The prime minister narrowly survived a vote of confidence among Tory MPs last month - but suffered a rebellion bigger than Theresa May.

Some 211 MPs voted for the prime minister, compared to 148 votes against - a majority of 63.

After PMQs, Number 10 said Mr Johnson would fight any fresh vote of confidence in him by backbenchers, and he believed he still had the support of the majority of his MPs.

Meanwhile, the resignations continued as the PM was probed by the Liaison Committee on matters of "integrity".

Conservative MP and chairman of the Transport Select Committee Huw Merriman seemingly posted his letter calling for the PM to go while in the same room as Mr Johnson.

A particularly damning letter from Mike Freer resigning as minister for exports and equalities cited "an atmosphere of hostility for LGBT+ people".

PM should 'take responsibility and resign'

Earlier at PMQs, Labour leader Sir Keir Starmer attacked the PM over his handling of the scandal, reading out the accusations levelled at Mr Pincher as a "reminder to all those propping up this prime minister just how serious the situation is".

In fiery exchanges at PMQs, the Labour leader said the list of resignations had left him with a "z list cast of nodding dogs" on his frontbench.

He also criticised those who have quit the government, saying they did not have a "shred of integrity" as they had failed to quit over other scandals to engulf Mr Johnson's administration.

Opposition MPs were not the only ones putting the boot in, with several on the Conservative benches using PMQs to tell Mr Johnson to go.

Gary Sambrook, an executive member of the 1922 committee of Tory backbenchers, which could be instrumental in the PM's future, said Mr Johnson "constantly tries to deflect from the issue, always tries to blame other people for mistakes, and [there is] nothing left for him to do than take responsibility and resign".

While David Davis, who called for the PM to go six months ago, reiterated his demand.

Put to him at the committee that a delegation of senior Conservatives were waiting at Downing Street, urging him to resign, the PM refused to be drawn on the reports.

"I'm not going to give a running commentary on political events, we're going to get on with the government of the country," he said.