So when he was appointed as Britain’s Ambassador to Washington, widely seen as the plumbest appointment in politics, most of the country was aghast. How could Sir Keir be so foolish? Surely he must have known that the rancid stench of such an appointment would linger? So last night, Kemi Badenoch pounced – tabling a motion that would force the government to admit just how much it knew when that foolish appointment was made.

All they asked for was the release of Lord Mandelson’s ambassadorial vetting file. Simple enough, no?

Either the vetting was thorough and revealed nothing that would disqualify, in which case publish it and be vindicated. Or the pages of that file were mired in sleaze and black rot of scandal, in which case the public must know why such an unsuitable candidate was waved through.

Sir Keir, in his characteristic fashion, somehow chose an even worse option – amend the motion to exempt anything he might find embarrassing. How terribly convenient! One would be forgiven for thinking there was something to hide.

Naturally, his attempts to contort his way out of this failed. Not because the Conservatives defeated him, but because the knife was stuck into his own back by his own team. Angela Rayner, the spurned former Deputy Prime Minister, spectacularly turned on her boss – the Red Queen got her daggers out, and plunged them deep.

Sir Keir must surely be able to hear the clock ticking in Downing Street.

The scandal itself beggars belief. If one can stomach looking at the content of the emails allegedly sent between Lord Mandelson and Epstein, they make for skin-crawling reading. Lord Mandelson, entailed and dispatched to glad-hand in Washington, had to resign within weeks when new Epstein files emerged.

Then came allegations that he had passed market-sensitive information to the paedophile financier.. Gordon Brown handed evidence to the police and dozens of MPs spoke out. Yet Sir Keir, who appointed him, self-evidently aware of the Epstein associations, stayed silent.

For years, Sir Keir railed against Boris Johnson‘s ‘sleaze’. He demanded resignations over garden drinks, birthday cake and rule breaking. He positioned himself as the great restorer of propriety, but now look at him. Cowering behind parliamentary procedure while his own party plots his removal.

This is not just mere hypocrisy, it is one of the worst political scandals in recent memory, and the Prime Minister is at its centre.

We should not be at the stage where the only way to rectify this issue in some way is for a gaggle of politicians to act in their own self-interest, and shaft the man under whom they serve. Sir Keir has only one card left to play to preserve what little is left of his reputation.

Do not wait to be pushed: jump.

If he resigns now, he can walk out of No 10 with whatever scraps of dignity remain, claiming he takes responsibility, that the appointment was an error of judgment he cannot defend. It would be honest.

We might even call it statesmanlike.

The alternative is to wait for his own party to force him out. The knives are being sharpened and the numbers are being counted. Brutus is selecting his toga, Longinus is reaching for his whetstone. Sir Keir must surely know this, for it seems everyone else does.

Only the timing remains in doubt. Tick tock, Prime Minister. Jump, or be pushed.