Keir Starmer tonight insisted he will not be dictated to on the winter fuel allowance axe as he ignored a revolt at Labour conference.
The PM stressed that the humiliating defeat in a vote in Liverpool was not binding, saying he had to take difficult choices.
Sir Keir was given the symbolic bloody nose by trade union leaders as the conference backed their motion calling for the reinstatement of universal winter fuel payments.
But, despite the humiliating vote result, party chiefs and Cabinet ministers insisted the Government would plough on with the policy to restrict payments to only those pensioners on means-tested benefits.
Speaking to Channel 4 News in New York this evening, Sir Keir said he and his ministers had made a difficult decision, taken because the last government left a £22billion black hole.
I do understand how, you know, colleagues in the Labour movement feel about this, he said.
This is clearly a difficult decision but a motion at conference doesnt dictate Government policy.
Sharon Graham, general secretary of Unite, celebrated after Labour delegates backed a motion calling for the reversal of Government cuts to pensioners winter fuel payments
Health Secretary Wes Streeting told the BBC that he and fellow Labour MPs dont have the luxury of ducking the difficult choices and decisions
Speaking to Channel 4 News in New York this evening, Sir Keir said he and his ministers had made a difficult decision, taken because the last government left a £22billion black hole
Labour delegates narrowly voted to restore universal winter fuel payments on the last day of what should have been a triumphant celebration for the new Government in Liverpool.
They showed their displeasure at one of the Governments first major policy changes by calling for the restoration of the cash lump sum for all retirees.
It came after days of protests, led by Unite and the Communication Workers Union (CWU), against the decision to make the payment means-tested, as part of cost-cutting plans by Chancellor Rachel Reeves.
Composite 15, moved by Unite and seconded by the CWU, was carried following a vote of Labour delegates on the conference floor.
But there was some disquiet at the decision in the room, with some delegates feeling it had gone the other way.
Sir Keir was not present for a debate on the controversial policy at the conference in Liverpool, with the PM attending a United Nations summit in New York.
He earlier refused four times to apologise for cutting winter fuel payments.
Although the loss is only symbolic, because the decision has been voted into law, it underlines the scale of anger at the Government on the issue.
Speaking after the vote, Health Secretary Wes Streeting said he and fellow Labour MPs dont have the luxury of ducking the difficult choices and decisions.
Mr Streeting told BBC Politics Live that party members should not lose sight of the fact we came into Government to find a £22billion black hole in the public finances.
Unlike our Conservative predecessors, we are not going to duck those difficult choices, pretend that you can just ratchet up borrowing and you can play fast and loose with the public finances, he added.
The thing about delegates to party conference, whether theyre from our constituencies or trade unions, they get the chance to put their points across and they get the chance to speak up on the issues they care about and give us the advice they think we should follow.
But, ultimately, its us - the Government, the Parliamentary Labour Party - that dont have the luxury of ducking the difficult choices and decisions.
So weve had to make those choices. And, let me tell you, people would not thank us if we duck the difficult decisions and then the country paid a much heavier price down the road.
Thats where the Conservatives took us; were not going back there again.
It came after days of protests, led by Unite and the Communication Workers Union (CWU), against the decision to make the payment means-tested, as part of cost-cutting plans
Keir Starmer has refused four times to apologise for stripping winter fuel payments from pensioners
Addressing conference, Ms Graham blasted ministers for cutting cash handouts for the old while leaving the super-rich untouched
Addressing Labours conference this morning to move her unions motion, Unite secretary general Sharon Graham blasted ministers for cutting cash handouts for the old while leaving the super-rich untouched
This is not what people voted for, its the wrong decision and it needs to be reversed, she said.
After the vote Jon Trickett, the former frontbencher who was the only Labour MP to vote against the winter fuel payment cut in the Commons, said: Unions and party delegates were not persuaded to vote for cuts to winter fuel allowance. The conference spoke for poorer pensioners.
It came after Sir Keir, who is in New York for the United Nations General Assembly, refused four times to apologise for making the change.
The PM was repeatedly challenged to say sorry to vulnerable old people who were losing out on up to £300, but blamed the Tories for putting him in this position.
He took the defiant stance in a bruising clash with Susanna Reid on ITVs Good Morning Britain before he headed for a UN summit in New York.
Asked how he could justify the cut, Sir Keir said: Well, its tough and I think the first thing to say and to explain is why we had to do it.
We inherited a really damaged economy, we did an audit and we discovered an undisclosed £22billion black hole this year, which we have to fix.
The PMs took a defiant stance in a bruising clash with Susanna Reid on ITV s Good Morning Britain before he headed for a UN summit in New York
The Unite union staged a protest at the Labour conference today ahead of a vote on the issue
Pressed if he wanted to apologise to pensioners, Sir Keir said: Well, I am really concerned that weve been put in this position.
When you inherit an economy with £22billion missing, it is a really difficult set of choices.
But what I dont want to do is to allow the economy to run out of control. What I want to make sure is that every single pensioner, there is that increase through the triple lock each and every year...
Told again that he had an opportunity to say sorry, the PM said: The people who should be saying sorry are the last government who left a hole of £22billion, and they should be sorry for that and they should apologise for that.
Reid persisted: So youre not going to apologise?
Sir Keir said: Ive come in to fix the mess, fix the problems, and thats tough, really tough decisions.
The cost of not doing it is to run the risk that we lose control of the economy again.
Im not going to do that because if I do, you will be saying to me in two or three years time, if we lose control of the economy, will you now say sorry for having lost control of the economy?
Pressed on if he wanted to apologise to pensioners, Sir Keir said: Well, I am really concerned that weve been put in this position.
The conference motion to reinstate universal winter fuel payments was originally set to be debated on Monday - but was rescheduled for after Sir Keir had given his big speech and departed amid rumours of backroom manoeuvring.
It called for means testing of the winter fuel allowance to be reversed and for an end to fiscal rules which prevent borrowing to invest, as well as the introduction of a wealth tax.
Ms Graham had already suggested the payment cut could leave vulnerable dead before she took to the stage.
And in a tubthumping speech she said: Friends, we are the sixth richest economy in the world - we have the money. Britain needs investment, not austerity mark two.
We wont get any gold badges for shaving peanuts off our debt. These fiscal rules are self-imposed and the decision to keep them is hanging like a noose around our necks.
She added: Yes, Britain is broken and, yes, the Tories have left the mess and, yes, they are to blame. But Labour is now in Government and we cannot keep making everyday people pay.
Senior CWU officials were at Labours conference today as they are attending the funeral in Scotland of the unions former assistant general secretary Andy Kerr, who used to be on Labours national executive.
Alan Tate, from the London CWU, said: For our members the important work that the Government, a Labour Government, has begun has been overshadowed by the winter fuel cut.
He added: The CWU has been inundated with emails and calls from our retired members worried about choosing between heating and eating.
Experts are warning this could increase the risk of illness or even death for vulnerable people this winter.
Now weve heard from both the Prime Minister and the Chancellor describe this cut as a tough choice.
But, conference, the tough choice is not about switching off pensioners heating this winter.
The real choice is about picking up the phone to the tech giants like Amazon and the ultra wealthy and making them pay their fair share of tax.
Mr Tate said Labour should be taxing the rich rather than taking away a lifeline for vulnerable people.
Despite the motion being carried at its conference, Labour reaffirmed its decision to cut winter fuel payments for millions of pensioners.
A spokesperson said: The Labour Party was elected on our manifesto commitment to sound fiscal rules, economic growth is our primary mission and we will take the tough decisions now to rebuild Britain and make every part of the country better off.