More than 30 backbenchers are said to be ready to vote against the Chancellor’s plans to make it harder to claim incapacity benefits and personal independence payments (Pip).

The changes will affect almost four million people with the aim of saving £5billion for the Treasury.

Richard Burgon, who was suspended last year for opposing the two-child benefit cap, told Times Radio there would be ‘the mother of all rebellions’ if the changes were not dropped.

Normanton and Hemsworth MP Jon Trickett confirmed he would vote against the changes, saying: ‘I will not be voting for cuts to poorest people on welfare benefits.

‘The Chancellor has other options. Picking on disabled people is not the right thing to do.’

And Brian Leishman, the Labour MP for Grangemouth and Alloa, said: ‘The Spring Statement had awful cuts that will impact disabled people.

‘The ”tough political choice” of cuts would be avoided if the government decided to tax multi millionaires instead. I told Disabled People Against Cuts that I’ll vote against cuts to disability benefit.’

The scale of the rebellion is unlikely to mean the change is blocked, due to the size of Labour’s majority after its landslide win in July’s election.

There were 4.45 million children estimated to be in households in relative low income, after housing costs, in the year to March 2024, data published by the Department for Work and Pensions (DWP) on Thursday showed.

The latest figure is the highest since comparable records for the UK began in 2002/03.

It rose from an estimated 4.33 million in the year to March 2023.

A household is considered to be in relative poverty if it is below 60 per cent of the median income after housing costs.

Save the Children warned that, without immediate action, ‘this could be the first Labour government that oversees a significant rise in child poverty – a record no-one wants’, and described the latest data as ‘a source of national shame’.

Ms Reeves today insisted she is ‘absolutely certain’ her welfare reforms will not push people into poverty, appearing to reject official warnings about their impact.

The Chancellor also denied there will be further tax rises or spending cuts at the autumn budget in order to balance the books, but stopped short of ruling them out entirely.

But amid warnings about the impact of the cuts, the Chancellor told Sky News: ‘I am absolutely certain that our reforms, instead of pushing people into poverty, are going to get people into work.

‘And we know that if you move from welfare into work, you are much less likely to be in poverty.

Normanton and Hemsworth MP Jon Trickett confirmed he would vote against the changes, saying: ‘I will not be voting for cuts to poorest people on welfare benefits.’

‘That is our ambition, making people better off, not making people worse off, and also the welfare state will always be there for people who genuinely need it.’

Alongside the official impact assessment, there were warnings about the effect of the welfare cuts from the Resolution Foundation.

The living standards think tank’s analysis said the combination of a weak economic outlook and benefit cuts fall disproportionately on lower-income families, and mean that average income for the poorest half of households is on track to fall by £500 on average over the next five years.

Speaking to broadcasters on the morning after her statement, the Chancellor also signalled she was not willing to make further cuts or tax rises at the autumn budget.

The Institute for Fiscal Studies, an economics-focused think tank, warned after her statement that Ms Reeves had left herself open to six months of ‘damaging speculation and uncertainty over tax policy’.

While the Chancellor restored her £9.9 billion headroom of spending power with cuts made at the statement, the IFS warned the buffer is small by historic standards.

And Brian Leishman, the Labour MP for Grangemouth and Alloa, said: ‘The Spring Statement had awful cuts that will impact disabled people.

This risks the need for further cuts, or even tax rises at the autumn budget, if Ms Reeves is to adhere to her self-imposed fiscal rules to not borrow cash to pay for day-to-day public spending.

Asked by Times Radio if it was the truth she would have to return at the autumn budget with more cuts or tax rises, the Chancellor said: ‘No, it’s not.’

Asked if this meant she could rule out these measures, Ms Reeves replied: ‘What I’m saying is that there are loads of things that this Government are doing that are contributing to growth.’

She pointed to planning reforms as an example, citing the Office for Budget Responsibility’s analysis this would add ‘£3.4 million to our public finances’ as a result of economic growth.

The Chancellor added: ‘That shows if we go further and faster on delivering economic growth with our planning reforms, with our pensions reforms, with our regulatory reforms, we can both grow the economy and have more money for our public services. And that is what I’m focused on.’