Jeremy Corbyn has said society owes a “moral debt” to women who lost out on years of state pension payments when their retirement age was raised.
The party’s policy to reimburse the women has been estimated to cost £58 billion.
Earlier, the director of the Institute for Fiscal Studies (IFS) criticised Labour’s plans, saying that many of the so-called Waspi women are “actually quite well off” and that the party has shown a “decisive lack of priorities”.
Questioned on Labour’s policy, which was not costed in the party’s manifesto, Mr Corbyn said: “We owe a moral debt to these women.
“They were misled. They’ve lost a lot of money.
“The women I’ve just been talking to have lost between £30,000 and £50,000 each because of this.
“They are dedicated people to their communities and their families, and they’re very angry about the way they’ve been treated.”
Mr Corbyn refused to say that the pledge to the Waspi women means going against Labour’s promises on borrowing only for investment, adding “the government is obliged to pay”.
He said: “It’s a moral debt we owe to these women and, had the court case gone the other way, or another court case goes against the government, the government would have to pay, the government is obliged to pay … What we’re saying is we will pay it.”
Mr Corbyn also met a group of Waspi women in Renishaw, north-east Derbyshire, and told them he was “proud” of the policy.
He said: “I’m very proud that we’ve got that clearly in our manifesto and I’ll be very proud to go into government and say ‘this is the policy on which we’ve been elected and this is the policy that will now be carried out to right the wrong and the injustice that’s been done to all of you’.
“I will do absolutely everything I can to make sure we win the election on December 12 and put that pledge into practice.”
Mr Corbyn added: “People understand the injustice that’s been done to you and the need for the country as a whole to accept the moral responsibility for putting it right.”
But earlier, director of the IFS, Paul Johnson, raised reservations about the Labour Party’s proposal.
Speaking on BBC Radio 4’s Today Programme, Mr Johnson said the policy’s estimated cost of £58 billion is “a very, very large sum of money indeed”.
He added: “I think there are two interesting things about that, one is the sheer scale of it, and of course it immediately breaks the promises they made in their manifesto just last week only to borrow to invest.
“So, they would need even more than their £80 billion tax rises if they wanted to cover that.
“The other, I suppose, is just a statement of priorities or decisive lack of priorities, because there’s so much money for so many things, but they’re not finding money, for example, to reverse the welfare cuts for genuinely poor people of working wage.
“Whilst some of these Waspi women really have suffered hardship as a result of not realising that this pension age increase is happening, although it was announced back in the early 1990s, many of them are actually quite well off.”
But shadow housing secretary John Healey was quick to defend Labour’s move, saying that it was not fully costed in the party’s manifesto as it is “not a regular spending commitment”.
Speaking on BBC Radio 4’s Today programme, Mr Healey said: “We’re righting this wrong.
“We regard this injustice as breaking that basic contract between working people and their government.
“People who have worked hard all their lives expect and anticipate a level of income to plan their retirement which was snatched for them by the Conservatives and the Liberal Democrats in 2011 in that Pensions Act.
“That’s why it’s a one-off compensation, that’s why it is dealt with differently from the departmental year-to-year spending, and that’s why we would draw, as any government does for this sort of thing, on a contingency fund.
“And it may well be that the Conservatives have to make this sort of payment if they lose the legal court case in the longer run anyway.”
Women expecting to retire at 60 were told they would have to wait longer when changes to the state pension age were accelerated in 2010.
In 2018 the retirement age for women rose to 65, in line with men.
Waspi women, the Women Against State Pension Inequality, argue that they were not given enough time to prepare for the changes.
Labour has said it would make individual payments averaging £15,380 to the 3.7 million women it claims were affected by the changes to the state pension age.