Labour backbenchers are preparing to side with Conservative MPs in an attempt to force Keir Starmer before a parliamentary sleaze probe over the Lord Mandelson scandal.
The Prime Minister faces accusations of misleading the Commons regarding the appointment of the ex-Labour peer as ambassador to Washington.
A parliamentary debate is expected this week to determine whether the matter should be referred to the Privileges Committee for formal scrutiny.
Senior Labour figures have privately expressed fears the Government may not secure enough votes to block the referral.
A party insider told The Sun: "We have a big majority but MPs can vote with their feet like they did on welfare."
One Labour MP also told the newspaper: "Watch out for the Privileges Committee a lot of Labour MPs are angry."
Should the vote fail, Sir Keir would face examination by the same committee that effectively ended Boris Johnson’s political career during the partygate scandal.
The allegation centres on claims that Downing Street exerted pressure on the Foreign Office to approve Lord Mandelson's appointment, which Sir Keir has denied at the despatch box.
The Prime Minister faces accusations of misleading the Commons regarding the appointment of the ex-Labour peer
| PAFresh controversy erupted following the disclosure of text messages sent by the Prime Minister to Lord Mandelson after his selection for the Washington role.
Sir Keir reportedly messaged the peer "you'll be brilliant" prior to the public announcement of the ambassadorship.
The Prime Minister is also said to have conveyed his eagerness about the prospect of working "side by side" with Lord Mandelson.
The revelations have intensified scrutiny of Sir Keir's handling of the appointment, which has already prompted the dismissal of Foreign Office permanent secretary Sir Olly Robbins.
KEIR STARMER - READ THE LATEST:
Sir Keir reportedly messaged the peer 'you'll be brilliant' prior to the public announcement of the ambassadorship
| GETTYConservative MP Saqib Bhatti launched a scathing attack on the Prime Minister, accusing him of disregarding the victims of convicted sex offender Jeffrey Epstein.
He declared: "Labour MPs need to decide pronto if they stand with the victims of abuse or Starmer who didn't care at all."
Meanwhile, SNP Westminster leader Stephen Flynn added: "Starmer knew Mandelson had continued his friendship with Epstein when he sent this message."
Conservative leader Kemi Badenoch told The Times that her party was deploying every available parliamentary mechanism to uncover the truth.
Kemi Badenoch said her party was deploying every available parliamentary mechanism to uncover the truth
| PAShe said: "There are many times when Starmer has said things at the dispatch box that were not true and I've let it go. This time he has done it repeatedly."
Mrs Badenoch accused the Prime Minister of dismissing blameless officials for his own errors and damaging relations between ministers and senior civil servants.
However, former Conservative Attorney General Dominic Grieve warned against what he described as "political games".
He said: "Seeing that this appointment is being explored during these processes and all the evidence is not yet considered, it is impossible to see how starting a reference to the Privileges Committee is either useful or indeed 'due process'."
A Downing Street source dismissed the Conservative push as a "ridiculous and baseless political stunt" timed to coincide with local elections.
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