Keir Starmer has suffered his biggest Commons rebellion since becoming prime minister as Labour MPs made clear their anger at the decision to means test winter fuel payments to pensioners.
A total of 52 Labour backbenchers failed to vote in favour of the controversial policy, while one - Jon Trickett - voted against it.
In addition, five former Labour MPs who were suspended by the party in July for not backing its policy on the two-child benefit cap, also voted against the government.
However, the Tories’ attempt to cancel the policy was still comfortably defeated by 348 votes to 228, even though Labour’s 167-seat majority was slashed.
Rachel Reeves announced shortly after becoming chancellor that the winter fuel payment - which is worth up to £300 - would only be paid to those receiving pension credit.
That means that around 10 million old people who used to receive it will no longer do so.
Labour has said the move is necessary to help fill the £22 billion “black hole” in the government’s finances it says the Tories left behind.
But critics have said the move will plunge many old people into poverty and could even lead to some of them dying from the cold.
Labour sources insisted that only 12 of the 52 MPs who failed to vote with the government had not had their absence authorised.
Explaining his decision to rebel, Jon Trickett said: “I fear that removing the payment from pensioners will mean that many more will fall into poverty this winter.
“We know that the consequences of pensioner poverty are devastating. It can even be a matter of life and death.
“I could not in good conscience vote to make my constituents poorer. I will sleep well tonight knowing that I voted to defend my constituents.”
Tory chairman Richard Fuller said: “The country should not forget that Labour made a political choice to make this callous decision that will hurt pensioners just as their energy bills are set to increase this winter.”
Lib Dem work and pensions spokesperson Wendy Chamberlain said: “Millions of pensioners will be left deeply worried about how they will get by this winter with this cut to the winter fuel payment.
“So many pensioners are already facing another winter of a cost of living crisis and this will make things worse.
“The damage left by the Conservatives to our economy is unforgivable but cutting payments to vulnerable pensioners is no way to bring about the change the country deserves.
“We’ll keep fighting this cut tooth and nail anyway we can, we’ll continue to be a constructive opposition to the new Government and we’re fighting for the real change people want to see.”
SNP Westminster leader Stephen Flynn said: “Voters in Scotland were promised ‘change’ but instead the Labour Party is wielding the austerity axe and cutting billions of pounds from public services and household incomes.”