Will Keir Starmer use his nuclear option to try to head off a leadership challenge?

The prime minister has one deadly weapon of last resort that he can use – or threaten to use – to try to cling to office. He has the power to call a general election. Or, rather, he has the power to advise the King to dissolve parliament.

Such a request would usually be granted, unless it was apparent that there was someone else who could command the confidence of the House of Commons. That is where our flexible constitution becomes complicated, because the Labour Party, with a majority of 168, should be able to unite behind an alternative leader to avoid the appalling prospect of going to the country in third place in the opinion polls.

But what if Keir Starmer insisted? What if he said that the people did not vote for Angela Rayner’s more left-wing programme at the last election and that they should be consulted about the change? What if he said that a Rayner-led government would not be in the interests of the country – and that he had to put country before party?

The prime minister’s “allies” have already warned that a leadership challenge might trigger a general election, without being specific about how this might happen. I imagine that the Samson scenario of Starmer bringing the temple down around him might be made more explicit to some Labour MPs tempted to nominate a candidate to replace him.

Threatening to call an election in which Labour is likely to be wiped out might not seem credible to a rational actor, but the way that mutually assured destruction works as a deterrent is that you can never be entirely sure that the other party will behave rationally.

These allies have already claimed that a change of prime minister might lead to “economic chaos”, as it is assumed that Rayner, possibly with Ed Miliband as her chancellor, would want to spend more and borrow more. One anonymous minister told The Times that Rayner would be “Labour’s Liz Truss”, which is a wild exaggeration, but there is some truth in the claim that the markets would be unsettled, both by the instability of change at the top and by the prospect of a further relaxation of grip on the public finances.

It seems that Starmer is prepared to fight hard to keep his job and that suggestions that he is so upset with himself about Peter Mandelson that he would resign voluntarily are wide of the mark. That idea, allegedly floated by a cabinet minister, was probably intended to destabilise him, which is another indication of the state of morale at the top of the government.

And there is one part of Starmer’s determination not to be pushed out that is justified. He should say what Tony Blair said in 2006, when the agitation from Gordon Brown’s supporters reached one of its peaks: “It is important for the Labour Party to understand, and I think the majority of people in the party do understand, that it’s the public that comes first and the country that matters, and we can’t treat the public as irrelevant bystanders in a subject as important as who is their prime minister.”

Constitutionally, there is no requirement for a general election when there is a change of prime minister, but politically it makes sense that the new leader should obtain their own mandate. Brown understood that, which is why he wanted to call the election that never was a few months after he finally made it to No 10. (Theresa May understood it too, which is why she went to the country in 2017 – although she then wished she hadn’t.)

It was fitting, then, that Brown, the expert in stable and orderly transitions, should be back on the media today offering advice to his successor about how to handle this one. “Perhaps he’s been too slow to do the right things,” Brown said, helpfully. Even more helpfully, he said: “Let’s judge what he does on what happens in the next few months when he tries … to clean up the system.”

In other words, Starmer has a few months. During which time, the Labour Party needs to come to its senses. Labour MPs need to realise that, although the prime minister won’t deploy his weapon of last resort and try to call an election, they cannot “treat the public as irrelevant bystanders” if they are going to change leader.

That means they cannot launch a leadership challenge at a time when Rayner is the likely winner and she is so distrusted by the wider electorate and the markets. The poll of Labour members carried out just before the Epstein files were published suggested that Wes Streeting has made up some ground, but he still came third behind Rayner and Miliband.

Until the so-called soft left of the Labour Party accepts that Streeting is the best choice to lead a fresh start for this government, it is not safe to contemplate a change. It would simply pave the way for Nigel Farage in 2029.

More and more, people should realise that it was a historic error for Labour in 1981, copied by the Tories in 1998, to take the choice of leader and prime minister out of the hands of MPs alone.

We have a recent example of what happens when party members choose a prime minister. It was unkind and inaccurate on the part of that anonymous minister to describe Rayner as “Labour’s Liz Truss”, but letting the members decide is dangerous – until such time as they are prepared to choose someone acceptable to the country as a whole.