The seven Labour rebels who voted with the opposition to end the two-child benefit cap were “totally out of order”, according to a senior party figure.
The MPs, including former shadow chancellor John McDonnell, were suspended from Labour for six months on Tuesday after they went against the party line to support the SNP amendment to the King’s Speech.
The now independent politicians stood by their decisions, with one, Zarah Sultana, saying she would “always stand up for the most vulnerable in our society”.
But speaking to Sky News’ Electoral Dysfunction podcast, Harriet Harman said she found herself “very despairing” of the rebels.
Explainer: What is the two-child benefit cap?
The former Labour MP told Sky News’ political editor Beth Rigby: “Nobody forces them to stand for election as a Labour MP. If they want to be independents, then be independents.
“But if you sign up to a party, then stick with your word. They’re not the victims here. They’ve broken their promises.”
Keep up with all the latest news from the UK and around the world by following Sky News
Ms Harman, who is soon to join the House of Lords as a Labour peer, said Prime Minister Sir Keir Starmer had been “completely clear before the election that he wasn’t going to be able to [end] the two-child benefit policy”.
And she said she “wouldn’t be surprised” if it was a policy he would “do something about quite soon”.
The ex-MP added: “[Sir Keir] cares about child poverty, as do people in the rest of the cabinet… they know about poverty from personal experience and it’s part of their ideological commitment.
“But they’ve got to do it in a way which doesn’t stuff the finances. You know, Liz Truss is quite a recent memory.”
Please use Chrome browser for a more accessible video player
Education Secretary Bridget Phillipson hinted to Sky News Labour could scrap the cap in the future.
The two-child benefit cap was announced by former Tory chancellor George Osborne in 2015 as part of the government’s austerity measures.
It means while parents can claim child tax credit or Universal Credit payments for their first and second child, they can’t make claims for any further children they have.
Labour MPs have long condemned the policy for dragging more children into poverty, with then shadow ministers calling it “vicious” and “heinous”, and many expected that if the party got into power, it would scrap it.
However, in 2023, Sir Keir ruled it out due to the state of the public finances, saying he would “have to make the tough decisions” if he got into Number 10.
Instead, the government has launched a child poverty taskforce to look at the best ways to more broadly tackle the issue.