Tory MPs have been facing a “toxic atmosphere” having to defend Boris Johnson over partygate.

William Wragg, Conservative MP, told the Commons today that he would be supporting the motion tabled by Labour calling for an investigation into whether Mr Johnson has willingly misled parliament.

He was speaking during a debate on the motion, which will see MPs given a free vote on whether to support it or not, and if it passes will see the Commons Committee of Privileges investigate the Prime Minister’s previous mistruths.

Mr Wragg said he “cannot reconcile myself to the Prime Minister's continued leadership of our country and the Conservative Party”.

He continued: “I care deeply about my colleagues. I know that a number are struggling at the moment. We have been working in a toxic atmosphere. The parliamentary party bears the scars of misjudgments of leadership.

“There can be few colleagues on this side of the House, I would contend, who are truly enjoying being Members of Parliament at the moment. It is utterly depressing to be asked to defend the indefensible. Each time part of us withers.”

Opening the debate earlier, Labour leader Sir Keir Starmer sought to strike a sombre tone and said the issue was more important than just whether Mr Johnson had been untruthful about partygate.

He also accused Mr Johnson of abusing the rules of Parliament - knowing that he could not be called a liar by others – to defend himself and cover up what he had done.

He explained: “It is a principle under attack, because the Prime Minister has been accused of repeatedly, deliberately and routinely misleading the House over parties held in Downing Street during lockdown.

“That is a serious allegation. If it is true, it amounts to contempt of Parliament. It is not, and should never be, an accusation made lightly.”

Liberal Democrat MP Alistair Carmichael intervened, saying there should be a vote at the end of the debate to ensure the public knew where their own MP stands on the issue.

He said: “At a time like this on an issue like this there should be no hiding place for anyone.”

Sir Keir replied: “I agree because we have duty here today in relation to this motion and in relation to these principles and if we fail in our duty, the public will not forgive and forget that we have done so.

“Because this will be the Parliament that failed. Failed to stand up for honesty, integrity and telling the truth in politics. Failed to stand up to a Prime Minister who seeks to turn our good faith against us. Failed to stand up for our great democracy.

“It’s not just the eyes of our country that are upon us, it will also be the judgment of future generations who will look back at what members of this great House did when our customs were tested, when its traditions were pushed to breaking point, when we were called up to stand up for honesty, integrity and for truth.”

Conservative MP Sir Peter Bottomley, the Father of the House, said it is “not the right time” for MPs to make a decision and MPs should wait until all investigations have been concluded.

Sir Peter went on to suggest “some part” of Labour moving the motion was to gain an advantage at the forthcoming local elections, adding: “I intend to have no part of that.”

Ian Blackford, the SNP Westminster leader, was not rebuked by the Commons Speaker despite describing the Prime Minister as a “liar”.

Usually MPs are not permitted to accuse others of lying in parliament, however due to the subject of the debate the speaker said he would make exceptions.

Mr Blackford said: “The Prime Minister of the United Kingdom is a liar. I genuinely don’t say that lightly and I don’t say it loosely.”

He continued: “He lied to avoid getting caught, and once he got caught, he lied again.”

Mr Blackford urged Tory MPs to support the motion for an investigation, as well as saying they alone had the power to get rid of their leader, adding: “Any other Prime Minister – including all of his predecessors as Conservative Prime Ministers - would have been long gone by now.”

MPs are due to vote on whether to allow a probe into Mr Johnson’s previous statements this evening, after the debate concludes.

It is expected to pass after the Government withdrew its amendment to the Labour motion, and allowed its MPs to vote freely.