More than 40 Labor MPs have warned the prime minister that plans to cut people with disabilities are "impossible to support" and called for a moratorium and change direction.

The letter from MPs spans new air inlets and veterans, from the left and right of the party, and when the House of Commons votes on the measure next month, Keir Starmer sets up Keir Starmer for his biggest rebellion in the Premier League.

Labor MPs have been widely concerned about the proposed changes, including a massive tightening of Individual Independent Payments (PIPS), savings of about £5 billion a year.

They will also involve cutting or freezing to make it impossible for people who apply for universal credit but are not suitable for work.

According to the Department of Internal Work and Pensions (DWP), planned disability benefits will affect 700,000 families already in poverty.

The proposal is expected to be voted on in June, and there are concerns that many MPs will be asked to approve the plan without properly understanding the consequences. The letter has been signed by 42 Labor MPs so far, which has brought the government to its biggest rebellion to date.

The letter said the proposals, presented in the Government Green Book, "caused great anxiety and concern among people with disabilities and their families."

It said: "Since George Osborne's biggest attack on welfare states in the years of austerity, the planned cuts of more than £7 billion are the biggest attacks on welfare states, and more than 3 million of our poorest and most vulnerable people will be affected."

"While the government may have correctly diagnosed the problem of the breakdown of the welfare system and the lack of job opportunities for those who can work, they have put forward the wrong medicine. Layouts did not create jobs, but they just created greater difficulties."

The letter calls on ministers to postpone any decision until they see a comprehensive assessment of the impact of any cuts and “hare a real conversation with people with disabilities organizations to redesign something less complex and provide greater support and address barriers people with disabilities face in trying to find and maintain employment”.

It continued: "We also need to invest in job creation and ensure that the law is strong enough to provide employment protections about discrimination. Without a change in direction, green paper will not be supported."

Signators include some MPs on the left side of the party, such as Diane Abbott and Kim Johnson, as well as a series of more middle back seat benches, with 14 air intakes from 2024, including Terry Jermy, Peter Lamb, Peter Lamb, Simon Opher, Lorraine Beaver and Cat Eccles.

The changes in benefits, proposed by Liz Kendall's work and pension secretary in March, will tighten the eligibility criteria for PIP so that people need to get 4 points in at least one activity to get a daily living allowance.

Similarly, while the basic credit rate for people who are looking for a job will rise by about £15 per week starting in April 2026, new claimants deemed unsuitable to work will cut the helpless benefits. Existing claimants will freeze support.

People under 22 years of age who want to receive a healthy top-up of universal credit will no longer be eligible for a plan being consulted.

Kendall said her department spends up to £1 billion a year to help people return to work.

When the plan was clarified, Labour MP Debbie Abrahams, who presided over the work and pension committee of the House of Commons, warned against “balanced books on the back of the sick and disabled.”

Although a series of personal back seat shelves expressed serious concern about these plans, the messenger led to the widespread belief that even the language that could not support the plan had the possibility of abstaining and objection.

So far, Starmer's government has only experienced the uprising in the Small Commons, partly because the 10th reaction that first took place was very powerful.

Downing Street suspended seven MPs shortly after the July general election when they voted for the Scottish National Party amendment to remove welfare restrictions for the two.

"The core of these reforms is the determination to help more people get into the job. We understand that there are some concerns. The Secretary of State is talking to colleagues and talking to colleagues, explaining why these reforms will help change people's lives."