An estimated 780,000 pensioners still eligible to receive the winter fuel payment will lose the benefit under planned cuts, according to the Government’s own equality analysis.

In a document quietly released on Friday night, the Department for Work and Pensions (DWP) also said that more than two thirds – around 71% – of those with a disability and 83% of those aged 80 or over would miss out.

Downing Street has said that a full impact assessment of the change, coming into effect this year, has not been carried out.

The figures, published in response to a freedom of information request, are based on “equality analyses” which “are not impact assessments and not routinely published alongside secondary legislation”, the DWP said.

Sir Keir Starmer and Chancellor Rachel Reeves have decided to means-test the benefits, worth up to £300, which they insist is necessary to help fill a “£22 billion black hole” in the public finances.

From this winter, only people on pension credit or certain other benefits will receive the payments, while about 10 million others are set to be stripped of the allowance.

However, in its FOI response, the DWP said that while those with a disability will be disproportionately likely to retain the payment, “around 71% – 1.6 million – of people with a disability will still lose entitlement”.

And about 880,000 people currently set to lose the benefit this year are pensioners entitled to pension credit who have not claimed it, according to the analysis.

The assessment assumes a five percentage point “loss aversion” increase in pension credit take-up, which the DWP said then cuts the number of eligible pensioners failing to claim to about 780,000.

The DWP said: “The Government has followed its legal and statutory duties ahead of introducing these changes and will continue to do so.”

The revelations have reignited a row over the policy, which has been attacked by both unions and opposition critics as it sets out to strip about 10 million pensioners of the support with their energy bills.

The Government has said the measures are part of efforts stabilise the economy and are expected to save about £1.3 billion.

Conservative Party chairman Richard Fuller said: “At the start of this week, Labour MPs marched through the lobbies to cover up the impact of the winter fuel cuts which will slash support for many pensioners in their own constituencies.

“This shocking new data, sneaked out by the Government, now shows 780,000 people who should be entitled to the payment will lose out as will 1.6 million people with a disability.”

He called on Labour to “immediately” conduct and publish a full impact assessment of “this harmful policy”.

In 2017, Labour claimed Conservative plans to means-test the winter fuel allowance could lead to almost 4,000 deaths.

Pressed earlier on whether an impact assessment of the policy would be published, Sir Keir told reporters travelling with him to Washington DC: “There isn’t a report on my desk which somehow we’re not showing, that I’m not showing, as simple as that.”

He said the Government was not legally required to produce one.