Sir Keir Starmer must face MPs again within 24 hours to answer questions about Sir Olly Robbins’ version of events in the Peter Mandelson scandal, Kemi Badenoch declared.

Former Foreign Office chief Sir Olly will address a group of MPs on Tuesday morning after the Prime Minister blamed him and his staff for the vetting fiasco.

And Sir Olly is expected to detail how he felt he could not tell Downing Street the disgraced Peer Lord Mandelson had failed vetting because it would undermine the process.

Mrs Badenoch, speaking as she secured an emergency debate on Tuesday, insisted Sir Keir must not hide behind another minister.

She said: “The House should have the chance to debate what he says at the earliest opportunity.

"That is why the House should be able to debate this before the forthcoming prorogation.

"At its core... this matter pertains to the Prime Minister’s catastrophic judgment.

"It pertains to his lack of grip... and his failure to ask the relevant questions.

"It would be unfair of him to palm this Debate off onto a junior minister who does not have the information and did not take the decision.

"This whole saga has been about the Prime Minister’s leadership.

"A real leader would come and answer these questions himself.”

In an explosive day in Westminster on Monday, MPs took pot shots at the Prime Minister's animosity over his decision to give Lord Mandelson the top diplomatic job, even though he failed security vetting, boiled over.

Provoking incredulity in a feisty Commons, Sir Keir told MPs it was “frankly staggering” that he was not told the Labour grandee had not passed checks and acknowledged Parliament should have known about it “a long time ago”.

The Prime Minister repeatedly insisted he only found out last Tuesday that UK Security Vetting (UKSV), the agency responsible for conducting assessments, had declined to give Mandelson vetting clearance.

He said: “A deliberate decision was taken to withhold that material from me...this was not a lack of asking. It wasn’t an oversight. It was a decision taken not to share that information on repeated occasions.”

And he was met with loud derision when he admitted that the whole debacle sounds like a fantasy.

“I know many members across the House will find these facts to be incredible, and to that I can only say that they are right,” he told the Commons.

“It beggars belief that throughout the whole timeline of events, officials in the Foreign Office saw fit to withhold this information from the most senior ministers in our system of government.

“That is not how the vast majority of people in this country expects politics, government or accountability to work, and I do not think it’s how most public servants think it should work.”

Labour MPs also joined the assault, as Dame Emily Thornberry, chair of the Foreign Affairs Committee, said: “Doesn’t this look like for certain members of the Prime minister’s team, getting Peter Mandelson the job was a priority that overrode everything else, and that security considerations were very much second order.”

Veteran MP Diane Abbott said Peter Mandelson “has a history” after resigning twice as a member of the Cabinet. Mocking Sir Keir, she asked: “It’s one thing to say nobody told me, nobody told me anything, nobody told me. The question is, why didn’t the Prime Minister ask?”

And Karl Turner, also an independent MP after being suspended by Sir Keir from the Labour group in Parliament, said: “Trust in the Prime Minister and in politics is diminishing as this sorry saga continues.”

The Prime Minister blamed Foreign Office officials who had approved Lord Mandelson’s developed vetting status, allowing him to see secret information as ambassador to the US, despite the recommendation of security experts not to grant clearance.

Sir Keir said he would not have proceeded with the appointment if he had known UKSV, the agency responsible for conducting assessments, had declined to approve the peer.

The Prime Minister fired the Foreign Office’s top civil servant, Sir Olly Robbins, after finding out last week that Lord Mandelson’s vetting status had been granted despite failing the UKSV check.

Sir Keir said: “At the heart of this, there is also a judgment I made that was wrong. I should not have appointed Peter Mandelson.

“I take responsibility for that decision, and I apologise again to the victims of the paedophile Jeffrey Epstein, who were clearly failed by my decision.”