The Tories have pledged to use “every mechanism” possible to reveal more information about Lord Peter Mandelson’s sacking.
Kemi Badenoch’s party is understood to have spent Sunday in talks with Commons officials to “make sure that we get answers” this week using any parliamentary procedures available.
One unnamed senior Tory said: “We’re looking at all Parliamentary mechanisms to get the release of these files.”
Keir Starmer’s future as Prime Minister was on the ropes last on Sunday, just days before Donald Trump’s unprecedented second state visit this week.
It was reported that Sir Keir did not see the full extent of the Labour grandee’s emails to convicted pedophile Jeffrey Epstein until Wednesday night, before sacking him as UK ambassador to the US on Thursday last week.
But Laura Trott, Shadow Education Secretary, said: “We know that Bloomberg put these allegations to the Foreign Office on Tuesday. I’ve been in Number 10 – there is no way that is not then reported into Number 10.
“This is what we’re going to be pushing for next week, and if you’re a Labour MP watching this now, you should be pushing for it too, because we will use every mechanism that is available to us to force the truth to come out.
“We need these documents. We need to understand what advice went to the Prime Minister and when who made these decisions.
“How have we ended up in a situation where the advice for the Prime Minister is to appoint the best pal of a convicted paedophile to be US ambassador?
“It is unacceptable. The British public will not have this, and the Conservative Party will make sure that we get answers.”
Downing Street was accused of “openly admitting” that it chose to prioritise Lord Mandelson’s “singular and outstanding talents” over the rights of Epstein’s victims.
Business Secretary Peter Kyle said these traits meant Lord Mandelson was deemed “worth the risk” to appoint as US ambassador despite the “strong relationship” with Epstein.
The Cabinet Office undertook an independent inquiry and presented information to the Prime Minister, Mr Kyle said.
He told how there were then “political conversations done in No 10″ in an apparent reference to follow-up questions Sir Keir Starmer is understood to have put to Lord Mandelson based on that information.
These are understood to have included why he continued contact with Epstein after he was convicted and why he was reported to have stayed in one of the paedophile financier’s homes while he was in prison.
“Now both of these things turned up information that was already public and a decision was made that based on Peter’s singular talents in this area, that the risk of appointing knowing what was already public was worth the risk.
“Now of course we have seen the emails which were not published at the time, were not public and not even known about, and that has changed the situation,” he told Sunday Morning With Trevor Phillips on Sky News.
Labour MPs’ fury over Sir Keir’s handling of this saga has sent rumours swirling about Manchester Mayor Andy Burnham’s leadership ambitions.
Sources have said that an MP, who is in ill health, is ready to step down – which would trigger a by-election which Burnham could conceivably stand in.
Referring to No10’s grip on the Mandelson scandal, Tory party chairman Kevin Hollinrake said: “This is not just poor judgment, it is a shameful betrayal of the victims and a blatant attempt to protect one of Labour’s most powerful insiders. We will demand answers in the House of Commons on Monday and press for the release of every relevant document.
“The Prime Minister cannot hide behind spin any longer. He must come clean, tell us exactly what he knew and when he knew it, and explain why the victims of a convicted paedophile were treated as collateral damage in order to save Peter Mandelson.”
Lord Mandelson’s friendship with Epstein was known before his appointment but reports this week showed their relationship continued after the financier’s crimes had emerged.
Emails published by Bloomberg on Wednesday included passages in which Lord Mandelson told Epstein to “fight for early release” shortly before he was sentenced to 18 months in prison.
He is also reported to have told Epstein, “I think the world of you”, the day before the disgraced financier began his sentence for soliciting prostitution from a minor in June 2008.
The emails were sent from an account which had long been closed and were not available during the vetting process.
It came as the brother and sister-in-law of Epstein victim Virginia Giuffre said Lord Peter Mandelson should never have been appointed to the UK’s top job in Washington.
Ms Giuffre, who died by suicide in Western Australia in April aged 41, was one of the most outspoken accusers of convicted sex offenders Epstein and his former girlfriend Ghislaine Maxwell.
Her brother Sky Roberts and sister-in-law Amanda Roberts gave their first broadcast interview in the UK when they spoke on BBC’s Sunday With Laura Kuenssberg.
Asked if Lord Mandelson should have been given the role in February, Mr Roberts said: “Absolutely not. He should not have been given the position in the first place.”
Ms Roberts said: “Why does it take us to have to pull out the skeletons for people to be held accountable?
“Our governments have allowed these people to hold their status and their title without shame, and so part of me is like, we should have done something sooner. He should have never been given that title.”
Ms Giuffre also sued the Duke of York for allegedly sexually assaulting her when she was 17 after she was trafficked by Epstein, which eventually led to Andrew paying millions of pounds to settle the case.
She alleged they trafficked her to the duke, with the duke denying the claim and saying they never met.