The mood among Labour MPs these days follows Edgar’s law. This states that the scale of any misfortune can only be measured against unknown future disasters. As Shakespeare has the banished son of the blinded Earl of Gloucester say in King Lear: “The worst is not, so long as we can say ‘this is the worst’.”

According to Edgar’s law, there is no opinion poll so gloomy for Labour that it can’t be followed by one even bleaker; no fiscal forecast so bad that the Treasury can’t aggravate it with contradictory signals on tax; no misgivings about Keir Starmer that can’t be amplified by malevolent briefing about a leadership challenge; no social policy so nauseating to the party faithful that it can’t be made grosser still with a relish of cruelty.

In that context, this week’s announcement of plans that aim to limit the number of refugees admitted to the UK, modelled on a notoriously mean Danish system, went down less badly with Labour MPs than might have been expected. There were sparks of backbench anger but no conflagration of dissent. No 10 was relieved. It helped that the home secretary had taken steps to explain the political imperative of the measures to colleagues in advance and in private. The plan landed on a rolled pitch.

Tightening asylum rules is not Labour’s comfort zone, but the current system is clearly failing and voters are angry. Most MPs understand Shabana Mahmood’s argument that tolerance and intercommunal harmony are easier to cultivate when there is confidence that the nation’s borders are secure. But many also struggle to see the pathway to greater compassion through a barricade of deterrent measures – threats to confiscate property and deport children – that advertise Britain as a country hostile to foreigners. The proposals may not have ignited instant rebellion. That doesn’t mean they were welcome.

Quiet backbenches can also be ominous. MPs have learned that everything is negotiable with a directionless leader of malleable conviction. What is announced today may be unannounced tomorrow. There is no need to rush over the top when victories can be won by attrition. Some of what looks like parliamentary discipline is really disdain – an acceptance among MPs and even ministers, after months of trying to decrypt the purpose of Starmer’s leadership, that there is none. Energy spent trying to influence him or participate in his project is wasted; nothing will come of nothing.

A common complaint is that Starmer is barely running the government at all, having delegated political judgment to Morgan McSweeney, his chief of staff. That isn’t to say the prime minister lacks executive dynamism, he just prefers not to mediate in departmental disputes or engage in long debates.

Starmer came to party politics late in his career, first entering parliament at the age of 52. He has no feel for Labour lore – the canon of historical arguments, campaigns, characters and cultural references that connect a leader to the wider movement and its sense of collective mission. He is said by people who have tried to engage him in discussion of ideas to be allergic to abstraction, seeing it as impediment to action. His innermost beliefs are a mystery even to the cabinet. As one senior Labour figure puts it: “Keir is highly unusual as a prime minister in giving the impression that whatever he personally thinks is none of your business.”

Wilful detachment from so much of what defines politics explains the reliance on McSweeney, whose strength in opposition was controlling party machinery and deploying it with ruthless efficiency. But the methods that worked in the run-up to July 2024 are not relevant to the challenge of running a country. The government isn’t a giant constituency party to be captured by a well-organised clique, then purged of irksome, wrong-thinking members.

The product packaged as Starmer in last year’s election campaign has also not delivered its purported benefits: managerial competence leading to national renewal. If Britain still had a two-party system, the memory of how bad things were under the Tories might prolong patience with Labour. But voters now channel their disappointment with a failing government to Reform UK, the Liberal Democrats, the Greens and, in Scotland and Wales, nationalist parties.

That presages a massacre of Labour candidates in council and devolved elections next May. It will be a moment of extreme peril for Starmer, assuming he survives that long. There are MPs who query whether it is worth waiting for defeat to prove that the leader is a dud when you could avert damage by ditching him now. Others argue that any opinion-poll bounce generated by fresh leadership is a precious, one-off resource, best held in reserve until much closer to a general election.

Missing from these calculations is agreement on the identity of a successor and how their programme may differ from the current government’s agenda. This flaw in the transition plan is cited by the prime minister’s defenders as one of many reasons to stick with the incumbent. A leadership contest would, they say, only accelerate voter flight from Labour. It would look weird and self-indulgent. It would prioritise party members’ grievances over wider public concerns. It would alarm markets as a symptom of instability. It would certainly not grow the economy or generate revenues to fund public services. The new prime minister would have no personal mandate.

While restive MPs may flinch at those warnings, they also hear in them the familiar, hollow knell of low ambition that induces despair at the status quo. It is the sound of failure to define Starmerism as anything more than a sequence of tactics for clinging on, warning that this is as good as it gets, betting that enough people will dread the thought of Nigel Farage in Downing Street to give Labour a second term. It is the defence of painful policy compromise as the means to an end, where the destination is just a labyrinth of endless means.

It is hard to summon loyalty to such a cause. And most Labour MPs have tried. They have stuck with the party line, defended it on the doorstep, obeyed the whips, believed assurances that their concerns were heard, feasted on crumbs of improvement in the prime minister’s performances, and been made to feel like mugs for extending so much benefit of the doubt. Not mutinous by disposition, they see mutiny as the only option left.

Regicide is fraught with risk, but is it riskier than pretending that the current ruler has answers to big questions that he never even names? Edgar’s law invites caution in ousting a sitting prime minister. The replacement could always be worse. But in the closing lines of King Lear, Edgar also articulates the quality so craved by Labour MPs in a future leader because it is painfully absent in the present one. “The weight of this sad time we must obey; Speak what we feel, not what we ought to say.”