KEIR STARMER has been forced to retreat, his offer not to apply disability benefit cuts to existing claimants thrashed out in negotiation with MPs all set to defeat the government on welfare “reform.”

It’s a serious defeat for a Prime Minister whose preferred means of handling dissent is to boot critics out of his party, and whose enforcers were telling MPs on this very issue they would never stand again on a Labour ticket if they dared defy him.

More so than his previous U-turn on winter fuel payments. The 126 Labour MPs who signed an amendment to block the cuts represent the biggest challenge to his authority to date — and government whips chose to make that explicit, warning would-be rebels this was a confidence issue that could force the PM to resign.

The fact such threats only increased the size of the rebellion cannot fill him with confidence: nor will the public interventions from Labour’s best-known regional magnates, London Mayor Sadiq Khan and Greater Manchester’s Andy Burnham, both thought to aspire to his job.

So this cannot be explained away as a response to changed circumstances. Starmer has been forced to back off by his party. But not to back down completely — and MPs should not accept a rotten compromise, one enshrining a two-tier benefits system in which support is slashed for those who become disabled in the future.

MPs said they objected to the failure to consult disabled people’s organisations or properly assess the impact of the cuts. This applies equally to the reduced cuts package he wants Parliament to swallow on Tuesday. MPs should hold their nerve and send the whole Bill back to the drawing board, as many already say they intend to.

The victory must be pressed home in other ways. Dame Meg Hillier, whose “reasoned amendment” attracted the 126 signatories, says Starmer needs to listen to backbenchers in future, rather than dictate policy and treat dissenting views as treason.

The same should apply well beyond the parliamentary party. Ever since he won the leadership on a fraudulent prospectus, Starmer’s approach has been dictatorial. Critics have been suspended or expelled, party branches told what they may or may not discuss, affiliated unions ignored, conference votes disregarded.

That culture, built up in opposition, informed the authoritarianism in government that sees back-bench MPs suspended for breaking the whip — and Labour continue down the repressive route of the Tories, attacking protest rights and now seeking to ban a peaceful direct action group under counter-terror legislation.

MPs should stick together, warning the whips against trying to punish anyone not won over by Starmer’s partial retreat. And unions should look to how MPs’ defiance can become a springboard for a wider policy revolt.

Because restricting attacks on social security to future claimants does not reverse austerity or rebuild our battered welfare state.

One factor in the scale of MPs’ revolt on benefit cuts is undoubtedly the recent passage of the assisted suicide Bill, which split Labour down the middle. Opponents highlighted the appalling treatment of disabled people in Britain, socially and institutionally, and how that magnifies the risk vulnerable people will be pushed towards an assisted death through denial of the right to live in dignity.

If MPs want reform that will enable disabled people to participate fully in society, including in the workplace when conditions allow, they need to block a Bill designed to cut costs and address the wider impact of austerity on societal exclusion: the disappearance of public toilets, the reduction in and cost of public transport, the social housing crisis.

Doing so means ripping up Rachel Reeves’s self-imposed fiscal rules, raising taxes on corporations and the rich and redistributing wealth. Different choices are available to the government and MPs have just demonstrated they have the power to make them when they have the courage to try.