Keir Starmer's prospects of survival suffered another hammer blow today as his fawning message to Peter Mandelson was revealed.
The PM contacted the New Labour architect to say he would be 'brilliant' as US ambassador - even though he had been warned over his friendship with Jeffrey Epstein.
The damning words are expected to be disclosed as part of the documents demanded by the Commons - but have so far been held back as Sir Keir fights for survival.
They could fuel a growing revolt against the premier, which has been inflamed by revelations that Mandelson was appointed against the advice of security vetting officials.
MPS are braced for a coup bid immediately after the May 7 local elections, which are feared to be cataclysmic for Labour. There have been mounting signs of unrest in Cabinet, with ministers offering only lukewarm support in public and privately criticising the decision to sack Foreign Office mandarin Olly Robbins.
Keir Starmer contacted Peter Mandelson to say he would be 'brilliant' as US ambassador - even though he had been warned over his friendship with Jeffrey Epstein
Sir Keir's main hope remains the lack of an obvious successor, with Angela Rayner still wrangling with HMRC over her unpaid stamp duty bill. Wes Streeting's allies have suggested they could form a 'dream ticket' alliance to take over.
Manchester Mayor Andy Burnham, the favoured choice of many MPs, is still outside the Commons after Sir Keir blocked him from standing in the Gorton by-election.
After Sir Olly's dramatic evidence to the foreign affairs committee about the Mandelson scandal on Tuesday, Cabinet Office permanent secretary Cat Little is due to be grilled this morning.
There will be another moment of high peril for the PM when his former chief of staff Morgan McSweeney appears before the committee on Tuesday.
But Sir Keir has ensured that he will not be subjected to an ordeal in the Commons afterwards, with Parliament set to prorogue on Wednesday morning until the King's Speech on May 13.
According to the Spectator, Sir Keir sent a message to Mandelson the day before his appointment was publicly announced in December 2024.
'You'll be brilliant in challenging circumstances,' he reportedly wrote. 'And after many years of our discussions, we get to work together side by side. I really look forward to that.'
Sir Keir has admitted he made an error of judgment in selecting Mandelson for the role. He was fired in September, but the controversy flared again in February when correspondence between the peer and Epstein was published by the US administration.
Ms Little last week told the PM that Mandelson had been granted high-level security clearance despite vetting officials recommending against it.
The civil servant had known since March about sensitive information linked to Lord Mandelson's vetting.
One senior source told the Daily Mail that the security vetting summary was very clear that Mandelson was not an appropriate candidate. 'A blind man in a blizzard could see Mandelson should have been rejected,' they said.
Downing Street previously said there is 'absolutely no suggestion' that Ms Little's position as Cabinet Office permanent secretary is in question.
Cabinet divisions have emerged over Sir Keir's handling of the process, including his decision to sack Sir Olly for failing to tell him about details of the vetting decision.
One Westminster veteran told the Spectator: 'I hope this will finally kill the absurd 'Keir Starmer is a decent man' narrative. He's a shitweasel whose sole political talent is blaming others for his own failings.'
Labour backbenchers have started openly voicing doubts about Sir Keir's future again, dashing hopes that his response to Donald Trump's Iran war could 'reset' his premiership.
Sir Keir has admitted he made an error of judgment in selecting Mandelson (pictured) for the role
Yesterday Work and Pensions Secretary Pat McFadden repeatedly declined to say whether he believed the sacking of Sir Olly was fair.
As pressure mounts against, Conservative leader Kemi Badenoch is pressing for Sir Keir to be referred to the Privileges Committee claiming he misled MPs.
The same committee found former PM Boris Johnson lied to the Commons over so-called partygate.
The Tory leader has suggested Sir Keir misled the Commons when he said 'due process' had been followed in the appointment of Lord Mandelson as British ambassador to the US, according to the newspaper.
He has denied misleading MPs.