The Keir hunters: Will it be Angela, Andy or Wes who pulls the trigger?

Just 16 months after Keir Starmer romped home with a majority of 174, the talk in Westminster isn’t about whether he can do it all again, but how long he will last as prime minister.

Will he be toppled before the May elections, or will he hang on until then? The working assumption has brutally shifted from a case of if to a question of when. It’s a symptom of the extent to which Labour’s victory was a product not of voter enthusiasm for a Starmer premiership, but of utter disillusionment with the Conservatives.

Second only to the question of when Starmer might go is the matter of who will succeed him. Labour’s internal politics have long been a story of competing factions with no love lost: the Corbynite hard left, the soft left, the socially conservative Blue Labour wing, the Blairite modernisers and the old right. But any contest to succeed Starmer is likely to boil down to a fight between the soft left and a candidate from the right.

In the former cohort, there are two standouts. Andy Burnham, the mayor of Greater Manchester, dubbed Labour’s “King of the North”, topped polls of party members earlier this year as the most popular candidate to succeed Starmer. He can point to the fact that he is seen as the best candidate by the general public, too. But since he so overtly challenged Starmer in the run-up to Labour’s autumn conference, his favourability ratings with members have taken a bit of a dip, reflecting the fact that some believe he has overplayed his hand.

By far Burnham’s biggest problem is that he is not in parliament. His ally Clive Lewis this week appeared to make a public offer to step down from his Norwich South seat to let Burnham run in a by-election – but even if that were to happen, it remains to be seen how it would go down with voters locally in a seat where the Greens would need a 15 per cent swing for him to take it.

Angela Rayner, until recently Labour’s deputy leader, is the other leading soft-left option, popular among both MPs and members. Her resignation after she failed to pay enough tax on a flat she bought in Hove has set back any leadership prospects, at least temporarily. Her allies reportedly think that a leadership election following next May’s local, Scottish and Welsh elections would be too soon for a comeback, but her status as a relatively new cabinet outsider could also give her more flexibility to be constructively critical in a leadership contest – it certainly worked for Lucy Powell, who has replaced her as deputy leader.

Burnham or Rayner would undoubtedly give the soft left their greatest chance of prevailing in any leadership contest. But if circumstances leave either unable to run, there are other senior MPs the soft left could rally behind, including Ed Miliband, currently the most popular member of the cabinet among party members, or Louise Haigh.

On the party’s right, health secretary Wes Streeting has long been seen as one of its most natural communicators, with the ability to sound human where Starmer does not. Last week’s No 10 briefing in which Starmer aides identified him as being on manoeuvres was tactically disastrous for the prime minister, but it shows the extent to which Streeting is seen as a threat.

But most recently, it is Shabana Mahmood’s Blue Labour approach to immigration that has really been making an impression. She is one of the few cabinet ministers to have developed a distinctive policy agenda – and is succeeding in communicating it to the public.

There are two key questions that allow us to evaluate all this below-surface jostling. The first is “What does the Labour Party need?” And the second is “Who is actually likely to win in any contest?” Unfortunately for Labour, their answers pull in different directions.

On the issue of what Labour would need in a new prime minister, the first very basic requirement is the ability to connect with voters. But beyond this, the existential dilemma for Labour is how to fight the next election. Should it focus on building a progressive coalition to keep Reform out? Or should it be taking on Reform directly on issues like immigration, as Mahmood is doing? The answer to that should shape who the party opts for, but a soft-left candidate is more likely to win with party members, who sit further to the left than Labour voters.

Ultimately, none of this has ever played out before. There has never been a challenge to a sitting Labour prime minister under these rules. Any faction that can coalesce 81 MPs around a single candidate can trigger a contest, and they can do this at a time that they think works best for them. Anyone else has to be ready to go once that button has been pressed.

This uncertainty has thrown Labour into something of a doom loop. The task of governing is made more difficult, because anyone who has leadership ambitions cannot afford not to have one eye on their potential campaign. It is why perhaps the best thing Starmer could do, for the country and his party, is to choose the right moment to resign next year.