Sir Keir Starmer has set up a confrontation with Labour rebels over welfare reforms, saying he will “lead from the front” in fighting for the changes.

The Prime Minister confirmed a Commons vote on the plans to squeeze sickness and incapacity benefits will go ahead on Tuesday despite 120 Labour MPs publicly backing a move to block the legislation.

He acknowledged it is “tough going” but “the important thing is to focus on the change that we want to bring about” rather than the “noises off”.

Sir Keir defended his leadership against accusations he had misjudged the mood in his party, insisting he is “comfortable with reading the room”.

At a press conference at the Nato summit in The Hague, he said: “Many people predicted before the election that we couldn’t read the room, we hadn’t got the politics right and we wouldn’t win an election after 2019 because we lost so badly.

“That was the constant charge of me at press conferences like this, and we got a landslide victory. So I’m comfortable with reading the room and delivering the change the country needs.”

He added: “Is it tough going? Are there plenty of people and noises off? Yes, of course, there always are, there always have been, there always will be.

“But the important thing is to focus on the change that we want to bring about.”

He said he is “very confident” he will lead the Labour Party into the next election, saying “it is really important that I lead from the front and take the long-term decisions about the future of our country”.

The Universal Credit and Personal Independence Payment Bill faces its first Commons test on Tuesday.

The plans restrict eligibility for personal independence payment (Pip), the main disability payment in England, and limit the sickness-related element of universal credit, with the aim of getting more people back into work and saving up to £5 billion a year.

Existing claimants will be given a 13-week phase-out period of financial support, a move seen as a bid to head off opposition.

But the fact so many Labour MPs are prepared to put their names to a “reasoned amendment”, a move which would stop the Bill in its tracks, shows how entrenched the opposition is.

Sir Keir indicated he is not willing to compromise.

“We have got to make the reforms to our system. It isn’t working as it is,” he said.

“It doesn’t work as it stands for people who desperately need help to get into work or for people who need protection. It is broken.

“We were elected in to change that which is broken, and that’s what we will do, and that’s why we will press ahead with reforms.”

The rebels argue disabled people have not been properly consulted about the plan and say further analysis is required before making any changes.

Social security minister Sir Stephen Timms said he is “looking forward to the debate” next week.

He told the Commons Work and Pensions Committee the changes need to be made urgently to cut the spiralling welfare bill.

Committee chairwoman Debbie Abrahams, who is one of the Labour MPs to have signed the amendment to block the legislation, asked why the provisions within the Bill had not been consulted on.

Sir Stephen said: “Essentially because of the urgency of the changes needing to be made.”

He said the cost of Pip had gone up from £12 billion before the pandemic to £22 billion last year, “and that is not a sustainable trajectory”.

Setting out the impact of the reforms, he told the committee that 370,000 people getting Pip under the current system would not be receiving it by the end of the decade.

“That will be a number of people whose income is lower,” he said.

“Of course, I’d love it for many of those to be able to move into work, and we’re going to be providing the employment support to make that ambition realistic for people in a way that it hasn’t been in the past.”

Mayor of Greater Manchester Andy Burnham has added his voice to the senior figures calling on the Government to reconsider.

He told BBC Newsnight: “When the PLP (Parliamentary Labour Party) delivers its collective wisdom in such numbers, it is invariably right. And it is right on this.”

His London counterpart, Sir Sadiq Khan, has said ministers “must urgently think again” about the plans, while Labour’s First Minister of Wales Baroness Eluned Morgan has also called for a rethink.

Work and Pensions Secretary Liz Kendall, who has already taken steps to soften the impact of the welfare Bill, has been locked in talks with backbenchers as she seeks to win over those opposed to the measures.

Meanwhile, Kemi Badenoch said the Tories will lend the Government votes to pass the legislation but only if Labour rules out tax rises in the autumn budget as well as reducing unemployment and lowering the welfare budget.