It was a dark week for the prime minister, with the departure of his longtime chief of staff Morgan McSweeney, who had become a deeply divisive figure and who took the hit for the appointment of Peter Mandelson as US ambassador, despite his links to the convicted child sex offender Jeffrey Epstein. But last Thursday morning had for a change been dominated by a different story.
Keir Starmer has bought some more time, there is a modest bounce in his polling, and he has had the well-timed fortune of the Munich security conference. His call there for the remaking of western alliances and taking the initiative on European defence cooperation has fumigated the air a little of the sense of imminent demise that has been swirling around him. But it will probably be a temporary hiatus.
Keir Starmer was on the brink of a leadership contest this week, but he pulled it back. That does not mean his rivals have gone away, with one of the most hotly tipped leadership candidates the health secretary, Wes Streeting. Earlier this week, Labour's leader in Scotland, Anas Sarwar, held an astonishing press conference calling for Starmer to resign.
Sir Keir Starmer nominated a former aide for a peerage despite being told he had been supportive of a councillor who had been accused of child sex offences, his ex-communications chief has claimed. The prime minister is facing continued questions over his judgment in appointing his former spin doctor, Matthew Doyle, to the House of Lords after he campaigned for a councillor who had been charged with having indecent images of children.
Keir Starmer arrived at Wednesday's Prime Minister's Questions with his claws sharpened. He reminded the Conservatives of Boris Johnson's misdeeds; the Liberal Democrats of their complicity in the austerity imposed by David Cameron's government; and Scottish National Party (SNP) of the corruption cases involving its previous leadership. Welldrilled Labour MPs cheered and applauded their leader. The immediate goal was to contain the fallout from the MandelsonEpstein scandal, which had come close to ending the British prime minister's brief tenure.
When he does go, what will the political death certificate give as the true cause of Keir Starmer's demise? It won't be the Peter Mandelson scandal, the policy U-turns or the bleak nights at provincial counting centres. All these are symptoms, not the disease. No, what is turning the guy elected just 19 months ago into an ex-prime minister is the slow realisation among ministers, colleagues and voters of one essential truth about the man: there is less to him than meets the eye.
"The distraction needs to end and the leadership in Downing Street has to change. That's why the distraction needs to end, and the leadership in Downing Street has to change... We cannot allow the failures at the heart of Downing Street to mean the failures continue here in Scotland. I have to be honest about failure wherever I see it - the situation in Downing Street is not good enough."
Westminster has seen plenty of leadership crises over the past decade. Sir Keir has faced questions over his leadership for months. But when a leader is under pressure, there are key questions worth asking: Is there a moment that will tip things over the edge - from crisis to the fall of a prime minister? How does it happen? Is there an obvious successor? Here are three moments that could prove dangerous for the prime minister.
