Labour has refused to publish a poverty analysis highlighting the impact of Rachel Reeves' decision to scrap winter fuel payments.
The Tories condemned the "shocking revelation" after the Government decided to axe the £300 payment from vulnerable older people.
Laura Trott MP, Shadow Chief Secretary to the Treasury, said: "It is disgraceful that the Treasury has a hidden analysis, which they are refusing to publish, which will show the terrible impact on 10 million pensioners of the cruel decision to scrap winter fuel payments.
"Once again, this is more damning analysis that the Labour government did everything they could to hide from the public and parliament - but they cannot hide from the consequences. They must now do the right thing and publish it immediately."
A Freedom of Information request was made to the Treasury in August which asked them to provide "the full internal policy impact assessment" or "any analysis associated with the poverty impacts of this policy" that was provided to ministers in advance of the announcement to scrap this benefit.
In their response, the Treasury confirmed that they did hold the information requested, but refused to provide it, instead using an exemption to claim that since it was part of the "formulation or development of government policy" more time was needed to determine whether its publication was in the "public interest".
The Tores said their confirmation of the existence of this analysis, and their refusal to publish it, is a "desperate attempt to avoid scrutiny and to hide this assessment".
Labour MPs had been forced to vote the policy change through parliament without seeing any assessment.
Another FOI request snuck out on Friday evening last week revealed the Government's Equality Impact in the decision.
It found about 780,000 pensioners who need the winter fuel payment will lose out on it.
And nearly three-quarters (71%) of disabled pensioners - about 1.6 million people - and 83% of people over 80 will lose their entitlement to the payment, the figures showed.
