PRIME Minister Sir Keir Starmer was facing defeat in his plan to slash benefits for disabled people after more than 100 Labour MPs backed an amendment to ditch the plans.

If the Tories decide to back the move, and the amendment is put to a vote when the Welfare Bill is debated next week, this would be enough to inflict a humiliating defeat on the government.

The MPs include a large number of normally loyal Starmer supporters, indicating the depth of political disquiet over the £5 billion cuts.

After U-turning on the cuts to winter fuel benefit, a further climbdown would fatally compromise the government’s credibility. 

However, many voices across the labour movement were demanding that Sir Keir abandon the cuts.

But the Prime Minister was doubling down today, telling the Cabinet that the welfare “system is currently failing people, trapping millions, telling them the only way to get help is to declare they will never work again, and then abandoning them without hope and opportunity.”

He later denied that the cuts were funding the enormous increases in arms spending he signed up to at the Nato summit in the Netherlands.

Sir Keir claimed: “It’s a misdescription to suggest that the defence spending commitment we’ve made is at the expense of money on welfare.

“We’ve made a huge commitment to the money we’re putting in to get people back to work.

“The welfare system is broken and that’s why we will press ahead with our reforms.”

He added that there was “a clear moral case” for the cuts. 

However, many MPs say they have found heavy-handed lobbying by Sir Keir and Chancellor Rachel Reeves counter-productive.

The rebel amendment instructs the Commons to cease progress on the Bill “because the government’s own impact assessment estimates that 250,000 people will be pushed into poverty as a result of these provisions, including 50,000 children.”

The MPs add that there has been no consultation with disabled people about the changes, and that the impact assessment from the Office for Budget Responsibility will not be published until the autumn.

Among the 108 MPs signing the amendment are 10 chairs of powerful Commons committees, including Meg Hillier of the Treasury committee and Debbie Abrahams of the work and pensions committee.

Ms Hillier said: “We don’t disagree that there is a need to reform welfare but it’s hard to deliver the proposed improvements in the proposed timescale. And disabled people must be protected.”

Vicky Foxcroft, the Labour whip who resigned over the cuts, has also signed.

Commons Speaker Lindsay Hoyle would need to select the amendment when MPs debate the legislation on July 1. Other amendments to block the Bill have been tabled by independent MPs and smaller parties.

The Tories, torn between their bedrock commitment to attacking the poor and the opportunity to embarrass the government, have not yet indicated how they will vote.

Transport union TSSA general secretary Maryam Eslamdoust said: “It’s vital that ministers pause and reconsider what they are trying to achieve with these welfare cuts which will only hurt those most in need across our society.

“Many MPs are clearly doing the right thing by challenging such injurious plans — they have listened to the many voices of disabled groups and charities.”

And Fire Brigades Union general secretary Steve Wright said: “It’s outrageous that the government is ploughing on regardless with welfare cuts in the face of such huge opposition among Labour MPs and the party as a whole. 

“It’s possible that Keir Starmer will be dependent on the Commons votes of Tory MPs to pass this new wave of austerity for the most vulnerable. 

“That’s a shameful thing for any Labour prime minister to do.”

James Watson-O’Neill, chief executive of the national disability charity Sense, said: “The government’s proposed welfare reforms would be devastating for disabled people, and we applaud the MPs pushing back against this unjust policy.”