Sir Keir Starmer has defended planned welfare reforms amid concerns among Labour MPs about expected cuts to the budget, insisting the existing system could not be justified on “moral” or “economic” terms.

The Prime Minister denied Britain would be “returning to austerity” under the changes but said the cost of benefits was “going through the roof” and on track to surpass the bill for the Home Office and prisons combined.

It comes as Downing Street seeks to reassure backbenchers uneasy with how cuts to the welfare bill would affect the most vulnerable in society.

The number of claimants on Universal Credit (UC) with a health condition or disability restricting their ability to work rose by half a million in a year to 2.5 million people, the latest figures show.

Sir Keir Starmer said too many people were getting ‘baked into’ the system (Philip Toscano/PA)

The latest figure for claimants across Great Britain as of December 2024 was up from two million the previous year.

Speaking on a visit to Hull on Thursday, Sir Keir said: “The welfare system as it’s set up, it can’t be defended on economic terms or moral terms.

“Economically, the cost is going through the roof. So if we don’t do anything, the cost of welfare is going to go to £70 billion per year. That’s a third of the cost of the NHS.

“That’s more than the Home Office and our prisons combined. So we’re making choices here.”

Sir Keir pledged to ‘protect those who need protecting’ but said there is no ‘bottomless pit’ (Oli Scarff/PA)

He said that “most people say to me” that they want more police officers on the beat and a criminal justice system working effectively.

“We’ve set up a system that basically says, ‘if you try the journey from where you are into work and anything goes wrong, you’ll probably end up in a worse position when you started.’

“And so understandably, many people say, ‘well, I’m a bit scared about making that journey.’ Therefore we’re baking in too many people not being able to get into work.”

Asked during a Q&A with journalists after his speech whether he accepted the changes would amount to return to austerity, he said: “We’re the party of work. We’re also the party of equality and fairness, but we’re not returning to austerity.

“That’s what I said before the election. That’s what I say now.”

The Prime Minister said it was especially “tragic” that so many young people are “already stuck in a system that won’t let them get to where they need to be” but that the problems were present across the board.

It comes after the latest figures showed that of the 2.5 million total UC claimants with a health condition or disability restricting their ability to work last year, 10% were under 25 years old while 38% were aged 50 and above.

Just over half (54%) of claimants were female.

Of the overall total, 14% – some 336,000 – were deemed to have acceptable medical evidence of a restricted ability to work.

Some 15% (366,000) were assessed as having limited capability for work (LCW), and 1.8 million (71%) were assessed as having limited capability for work and work-related activity (LCWRA).

The North East had the highest proportion in England of UC health cases relative to overall UC claimants, at almost four in 10 (39%).

This was followed by the South West and North West (both 36%), while the lowest was London (27%).

At Prime Minister’s Questions on Wednesday, Sir Keir faced a backlash over the rumoured welfare cuts, with one Labour MP pleading with him to make the “moral” choice.

Richard Burgon said that disabled people were ‘frightened’ (Jane Barlow/PA)

Richard Burgon told the Commons that disabled people are “frightened” as he urged Sir Keir to introduce a wealth tax instead of “making the poor and vulnerable pay”.

Sir Keir pledged to “protect those who need protecting”, but later added there is no “bottomless pit”.

The PM blamed the Conservatives for having “left a broken welfare system, which locks millions out of work, that is indefensible, in my view, economically and morally”.

He added: “Of course, we need to support people who need support, we need to help those who want to work to get back into work, and I think there’s a moral imperative in that.”

But he added: “This isn’t a bottomless pit, and we must kick-start growth to get the economic stability that we need.”