Caroline Abrahams, of Age UK, said: “Many older people are reeling from the news that they are losing their winter fuel payment, so we fervently hope that there are no more nasty surprises to come.”

Warning that pensioners are “frightened” about what could be heading their way, she said: “The Government’s decision to brutally means test winter fuel payments came out of the blue and as a complete shock, so it’s not surprising that some older people are telling Age UK that they are frightened of what they may do next.”

Conservative leadership candidate Robert Jenrick said: “Under Labour, pensioners could be nearly £1,000 a year worse off, which for many is a cost they simply can’t afford.

“Keir’s war on pensioners is putting Labour’s own political interests above any sense of right and wrong.”

Eamonn Donaghy, of Later Life Ambitions, which represents more than 250,000 older people, urged ministers to come clean with pensioners about whether a council tax hike is coming.

He said: “By refusing to confirm the status of the single person discount the government is piling uncertainty and stress on to a pensioner population that is already reeling.

“Older people worrying about how they are going to cope when the winter fuel payment is withdrawn face finances at breaking point if yet another benefit is taken from them. This Government is in danger of appearing tin-eared at best and downright uncaring at worst unless they turn back from what feels like an assault on pensioners and their finances.”

James Cleverly, another of the Tory leadership candidates, said Labour was “picking the pockets of pensioners and widows” because they have “hiked pay for their union bosses” and “now have to find a way to fund it”. Fellow candidate Tom Tugendhat also attacked the Prime Minister and the Chancellor, saying: “Starmer and Reeves have made a clear choice to leave our pensioners, who have worked hard all their lives and paid into the system, £1,000 poorer and more vulnerable this winter.”

And Tory MP Saqib Bhatti accused the Chancellor of staging a “bonfire of support for the most vulnerable”.

Sir Keir’s Government last week won a vote to restrict winter fuel payments but activists warn older voters will not forget this controversial decision.

“We have long memories,” said Dennis Reed, of Silver Voices.

Urging the Government not to axe the council tax discount, he said: “That has really got to be stopped because that would be a hammer blow to older people, especially those who are recently widowed.”

Conservative MP Louie French, who challenged the Prime Minister in Parliament last week on the issue, said: “It’s unfair and unaffordable to ask single and, in many cases, widowed pensioners to pay more at the same time Labour is cruelly removing the winter fuel payment with little notice.”

Former Labour minister Jeff Rooker, now a member of the House of Lords, said: “Removing the 25 per cent council tax
discount for single dwellers without reforming council tax would be political immaturity of a very high order.”

The discount for a single person on a band D home is £543 in Gateshead, £539
in Nottingham and £523 in Bristol.

It is £521 in Walsall, £519 in Northumberland and £511 in Liverpool.

Campaigners are continuing to press the government to u-turn on the winter fuel payments decision, and the disclosure that
71 per cent of pensioners with a disability – 1.6 million people – will lose the benefit has only heightened anxieties.

The figure is included in an assessment carried out by the government which it has now published in response to Freedom of Information requests.

It shows 83 per cent of those aged over 80 will lose the payment, as well as 90 per cent of those aged 66 to 79.

Laura Trott, Shadow Chief Secretary to the Treasury, said: “The publication of these analyses is a damning indictment of this entire Labour government.

“Not only do these reports confirm that thousands of pensioners will suffer this winter as a result of Rachel Reeves’ cold-hearted decision, but they were also hidden until after Labour forced their MPs to vote through this cut. It is a downright disgrace. Labour have cut winter fuel payments for 10 million pensioners knowing the horrific impact it will have, but they will not be able to hide from the consequences of it. We will bring them to task every step of the way.”

The MND Association has also urged the government to think again.

Forty MPs from eight parties signed a letter to the Chancellor which warns that motor neurone disease “causes significant muscle wastage, reducing the body’s natural insulation and making it much harder to retain heat”. Stating that households affected by the disease face “astronomical energy bills during the winter,” they say: “We are deeply concerned that the means-testing processes which will now be used to determine eligibility for winter fuel payments take no account of these unavoidable costs.”

Joanna Elson, of Independent Age, said: “It is essential that the upcoming Budget does not include measures that risk plunging older people on a low income further into financial hardship.”

A Treasury spokeswoman said: “Following the spending audit, the Chancellor has been clear that difficult
decisions lie ahead on spending, welfare and tax to fix the foundations of our economy and address the £22billion hole inherited by this Government.

“Decisions on how to do that will be taken at the Budget in the round.”