David Lammy turns on Keir Starmer and says he warned PM about Peter Mandelson

Instead, he was in favour of extending the term of Dame Karen Pierce as ambassador, as she is said to be well-connected within Donald Trump's inner circle.

Mr Lammy, who was Foreign Secretary at the time Mandelson was appointed, represents the first cabinet minister to openly go against Sir Keir Starmer on the Mandelson scandal, though he is not the first MP.

Former Deputy Prime Minister Angela Rayner has also told friends she was against the appointment.

Ms Rayner, who resigned from her post amid a scandal of her own when she revealed she had underpaid stamp duty on her flat in Hove, is also said to be "ready" to launch a leadership campaign, according to the Daily Mail, with Sir Keir's future in the balance following the scandal.

She could face a challenge from Net Zero Minister Ed Miliband, who is said to have seen the path back to the top open up.

Health Secretary Wes Streeting has also long been touted as Sir Keir's successor. His allies accused Ms Rayner's team of "nakedly trying to exploit" the Epstein scandal "for their own political interests".

In response, Ms Rayner's friends suggest that any bid from Mr Streeting could be affected by his own close links to Mandelson.

The Health Secretary admitted to deleting an old photo of the pair together on social media earlier in the week.

"To be honest, if I was Wes, I would be worried about what is going to come out from this disclosure – obviously, he is close to Mandelson," one ally of Ms Rayner said.

"It may be that there is nothing seismic, but a lot of my colleagues would probably think twice about backing him at this stage – it’s a bit of risk."

Mandelson is now facing a police investigation into whether he committed misconduct in public office after the Epstein files appeared to show he leaked highly sensitive Government information to the disgraced financier during the height of the financial crash in 2008.

Gordon Brown, the Prime Minister at the time, says he "greatly regrets" appointing Mandelson as Business Secretary.

While insisting Sir Keir is "a man of integrity" who "wants to do the right things", Mr Brown suggested he had acted too slowly in the matter.

"Perhaps he’s been too slow to do the right thing. But he must do the right things now," he wrote in The Guardian, urging the Prime Minister to act decisively.

Meanwhile, Ian Byrne, Labour MP for Liverpool West Derby, said on Friday he "needs a miracle", while Simon Opher MP called for a "clearout" at No10, including Chief of Staff, Morgan McSweeney.

Mr McSweeney is said to be considering his future at No10 following the scandal and calls for him to be sacked.

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