Jeremy Hunt has called on the cabinet secretary, Simon Case, to prevent the release of a review by the Office for Budget Responsibility into his spending plans, which is scheduled to be released on the day of the budget. The former chancellor has accused Rachel Reeves of politicising the Office for Budget Responsibility, after she announced she would release a review into the spending forecast published during his time at the Treasury. Government sources have briefed that the review may give Reeves proof that there was a £22bn “black hole” in spending this year. Hunt has been scathing about the idea that a black hole in spending exists and said he had not been contacted by the watchdog or the Treasury about the review, even though he was running the finance ministry until the election in early July. The former chancellor wrote to the OBR this week but on Tuesday escalated his concerns to Case – asking him to make a judgment call about whether publishing the report at the same time as the budget was politically appropriate. Hunt said the OBR had assured him it would not comment on the conduct of ministers. He said there was “no constitutional precedent” for a review commissioned by a current government into the conduct of a previous government not to be shown to those involved before publication. Hunt said he was a strong supporter of the OBR but added: “Straying into political territory and failing to follow due process like this demeans it and also is deeply problematic for perceptions of the impartiality of the civil service.” He asked Case whether he had advised the OBR that it was acceptable to publish the review on budget day and to undertake that the report has no content that could be used politically to attempt to discredit him. He asked Case whether the OBR had been advised about whether to consult the previous government. Hunt said: “I would ask you, on the basis of the above evidence and as a matter of basic procedural fairness to review whether you still feel it is acceptable for the OBR to publish this review on the day of the budget. I strongly urge you to protect its political impartiality and ensure that even the most basic due process is followed.” Reeves hit back at Hunt during Treasury questions in parliament, suggesting he was trying to hide from scrutiny. “It is important that we don’t deny the seriousness of the situation we face. With the black hole in the public finances, combined with lashing out at independent economic institutions, suggests that he has got more in common with Liz Truss and Kwasi Kwarteng than perhaps we thought,” she said. “I watched my party lurch towards an ideological extreme and deny reality, and as a result we spent years in opposition. The shadow chancellor risks taking his party down the same path.” Asked if the government was using the OBR as a political tool, a No 10 spokesperson said: “No, the prime minister is clear that this government is going to back the independent OBR, not trash it. “The answer is not to blame the referee, face up to the challenges we faced and be honest about the trade-offs and choices the government face, not pretend they don’t exist. In an article for the Times, Hunt said it was a matter of “procedural fairness” that he should be allowed to respond. I would have explained how it would have been perfectly possible to deal with any pressures within our fiscal rules,” he said. “Then, instead of a phoney debate about fictitious black holes, we could have focused on the real issue at this budget, which is how to address the longer-term pressures on public finances in a way that funds our public services and fosters growth. The OBR must be politically impartial because the public and markets need to know that it is holding the government to account without fear or favour.” Government sources have previously suggested to the Sunday Times that the report will put to bed any suggestion that Reeves had overstated the fiscal peril the government had discovered, saying: “Sunak and Hunt won’t be able to say this did not happen on their watch.”