This is the end, beautiful friend. It is the tragedy of almost all prime ministers that they are the last person to realise the game is up. Their race is run. The backbenchers are the first to know. They spend time in their constituencies. They get it in the neck from voters who have had enough with whoever is in No 10. They are the ones who get told nothing seems to work any more and that the prime minister has to go.

Then comes the cabinet ministers. They are more protected from the real world and may feel a residual sense of loyalty to the person who gave them a job. But even they are not immune to the tsunami of discontent.

On Tuesday, you could see the scales fall from Ed Miliband’s eyes. Mid-interview, he had a lightbulb moment,. Just why was he bothering to defend the indefensible. Sod it, he thought, and just said what was on his mind. That appointing Peter Mandelson had always been a catastrophic mistake.

Later the same day, Yvette Cooper found herself on the wrong end of a question about attempts by No 10 to find a diplomatic post for Matthew Doyle, Keir Starmer’s former head of communications and close friend of a convicted sex offender. Yvette didn’t even try to soft soap it. It had been wrong, she said.

Then on Wednesday, Pat McFadden, Starmer’s most loyal of ministers, refused three times in a radio interview to say Keir had been right to sack Olly Robbins. Pat had a smidgeon of self-respect left and he was determined to preserve it. If Keir has lost McFadden, he’s lost almost everyone. Cabinet meetings are now largely sullen affairs. No one wants to look Keir in the eye.

Starmer, though, fights on. Stuck in the parallel world of his landslide majority. He wants to believe he can still make a difference. That he is a good man with a lone moral compass. The right man – the only man – who can lead the country at this time. But you can see the light dying in his eyes. A darkness visible. Sunken hollows where there used to be a sense of purpose. Where dreams come to die. Frustration. Despair even. That everything that can go wrong has gone wrong. And then still more goes wrong.

Still, there are some consolations. Not least that when he is finally forced to resign, it will be nothing to do with the leader of the opposition. It’s almost as if Kemi Badenoch is playing a strange game in trying to maintain Starmer in Downing Street. How else do you explain her latest outing at prime minister’s questions on Wednesday? With the ongoing scandal of Peter Mandelson’s appointment as US ambassador, you’d have thought all that Kemi needed to do was just turn up and tap in the open goal.

All that was required of Kemi was to turn up and say six times: “What on earth made you think that Mandy was the right person for Washington? Which bit of being sacked twice for breaking the ministerial code, being close friends with Jeffrey Epstein and passing privileged insider information to a bank did you somehow miss?”

That is Starmer’s real crime. His failure. That he was a mere bystander prime minister. A spectator in Downing Street as Morgan McSweeney set about finding plum jobs for all his mates. That is the question that’s troubling his Labour MPs. That is the question on the minds of everyone in the country. We didn’t need to do any vetting on Mandelson to reach the conclusion he was a wrong’un. His nickname of the Prince of Darkness could have been a clue. We’d done our due diligence over the past 30 years.

Instead, Kemi tried to turn PMQs into a matter of process. And not only disappeared up several cul-de-sacs but turned something that could have been box office into something rather dull. Largely because it was not even clear if she understood the process she was trying to critique. All of which let Keir off the hook, once he had apologised again for appointing Mandelson. He seems to think that’s a get-out clause. As if that wipes the slate clean. As a barrister he ought to realise that cases are rarely that simple.

There was an air of desperation to Kemi’s questioning. She’s had three goes at trying to prove that Starmer had deliberately misled the house – first on Monday during Keir’s statement, on Tuesday in the opposition day debate and again at PMQs – and she’s failed each time. Largely because Starmer hasn’t misled the house. He’s guilty of all sorts of things but not this. But Keir lying is Kemi’s obsession. She can’t help herself. So she ties herself in knots.

It was also ironic to hear of Kemi complaining of No 10 putting pressure on Olly Robbins. The Tories have long argued for a civil service that does the government’s bidding. But at the first sign of one, they cry foul. The real point that Kemi kept missing was that the correct processes in Mandelson’s appointment were followed.

The processes themselves might have been hopelessly inadequate but that wasn’t Starmer’s fault. No 10 might have put pressure on Olly to expedite the clearance and bypass the vetting process but Olly was adamant in his testimony that the pressure had no effect on his decision making. Other opinions are available on this but for the time being we have to take Robbins’s word for it. Kemi might also have made more of No 10’s “jobs for the boys” culture that sounded out a sinecure for Doyle. But she blew that one too.

So Starmer will probably chalk this one up as a win. A small one. Insignificant in the grander scheme of things. An elephant trap avoided. But the Mandelson saga is not going away. On Thursday we get the cabinet office permanent secretary in front of the foreign affairs committee. Next Tuesday it’s McSweeney. Get in the popcorn.