Rachel Reeves is being “vindictive” if she frees up billions of pounds for investment but refuses to help struggling pensioners this winter, campaigners warned.

The Chancellor is planning to tweak rules to unlock £50 billion and changes by the Bank of England mean more money will be available in next month’s budget.

But Ms Reeves is sticking to plans taking up to £300 in fuel payments off 10 million over-65s.

Silver Voices accused the government of making a clear choice to target pensioners.

Director Dennis Reed said: “There is a certain amount of flexibility in the budget. If she doesn’t reverse the cuts all we can conclude from that really is this is vindictiveness.

“The money is clearly there so it would be a question of the Chancellor not wanting to spend money on older people who are going to be cold this winter.

“She has said on many occasions ‘we do not want to do this’. It will be very clear that if she does not reverse it, it will be very clear that she did want to do this and so did the Prime Minister and they will be judged on that basis.”

Ms Reeves is axing the universal winter fuel allowance, which is £200 for pensioners under 80 and £300 for those over to save £1.5 billion.

Instead, only retirees claiming pension credit and some other benefits will be eligible.

It means the 11.4 million people currently in receipt will drop to just 1.5 million.

But the Chancellor is planning to tweak the fiscal rules she committed to before the general election that call for day-to-day spending to be brought back into balance within five years and to get debt falling at that point.

Ms Reeves is expected to strip out student debt and change the way the government measures debt.

It would mean there is an extra £50 billion available to spend on capital projects, such as building projects, but not for everyday spending such as winter fuel payments.

But an extra £10 billion is expected to be freed up by the Bank of England’s decision to slow the pace of its quantitative tightening programme, which reduces losses to the Treasury from bond sales.

Treasury sources insist that the £50 billion predicted is hypothetical and any rule changes would be more complicated and likely lead to a lower figure.

Shadow Treasury Minister Gareth Davies said: “Labour’s plans to fiddle the figures and borrow billions would increase inflation and interest rates – with Express readers left to pay the price. “So rather than messing with the public finances and racking up billions in debt they should instead prioritise halting their cruel scrapping of the winter fuel payment for the ten million pensioners who face choosing between heating and eating this winter.”

Caroline Abrahams, charity director at Age UK, said: “At Age UK we recognise that the public finances are challenging, but if additional funds do become available to the Government this would undoubtedly further strengthen the case for measures in the Budget to support the poor, sick and disabled pensioners this winter who will struggle to stay warm without their Winter Fuel Payment.”

The National Pensioners Convention has organised an event in parliament when MPs return to warn that cutting the payments will be a “death sentence” for many older and vulnerable people.

All 650 MPs have been invited to listen to campaigners, charities and unions about concerns over the changes.

Jan Shortt, NPC General Secretary said, “It is testament to the seriousness of this issue that so many organisations and groups, representing so many sectors of our society will be taking part in this important Lobby of Parliament.

“The impact of the cuts will not just plunge up to another two million older and vulnerable people further into poverty, it will undoubtedly result in deaths as many are too frightened to turn on their heating or eat hot food.

“I hope MPs, and crucially the government, hear our pleas on 7th October to at least delay the decision, and meet with those who understand the pressures on our oldest and most vulnerable to find another way through. It’s not too late.”

Morgan Vine, Head of Policy and Influencing at Independent Age said: “Our helpline is continuing to hear from lots of anxious older people who are living on a low income.

“This group are incredibly worried about the winter fuel payment changes. Many fall just outside pension credit eligibility and are telling us that they don’t know how they will make it through this winter and that they’ll be forced to make severe cuts to essentials like heating and food. This cannot be right.

“Ahead of the Budget, we’re calling on the Chancellor to not make this change to the winter fuel payment now.

“Means-testing it with such little warning will have a serious impact on too many financially insecure older people this winter.

“Instead, urgent action is needed from the UK Government to ensure that in the short term everyone who needs pension credit receives it, so that people on the lowest incomes in later life can be better supported.”

Shadow Treasury Minister Gareth Davies said: “Labour’s plans to fiddle the figures and borrow billions would increase inflation and interest rates – with Express readers left to pay the price.

“So rather than messing with the public finances and racking up billions in debt they should instead prioritise halting their cruel scrapping of the winter fuel payment for the ten million pensioners who face choosing between heating and eating this Winter.”

A Treasury spokesman said: “We won’t comment on speculation about headroom but are protecting Winter Fuel Payments for those pensioners who need it most and the Triple Lock means millions will see their full new State Pension rise by around £1,700 over the next five years.”