Andrew Lansley has been accused of covering up the risks posed by his NHS reforms by refusing to publish an internal Department of Health assessment.
The information commissioner ruled last November that the document should be published as there was a "very strong public interest" in the information given the extensive changes due to be made to the health service as a result of the government's Health and Social Care Bill.
However Lansley appealed the ruling, arguing it would make civil servants and ministers scared to discuss the pros and cons of different policies in the future.
Labour hopes to force a vote on the issue following a Commons debate on Wednesday afternoon. Shadow health secretary Andy Burnham told MPs there was a "conspiracy of silence". Several Labour backbenchers chipped in with cries of "what are you hiding?".
"What are the precise risks he [Lansley] and the prime minister are taking with the NHS, how serious are those risks, and doesn't the public have a right to know?" he said.
"Instead members of this House have been asked to approve the most far reaching reorganization to this country's best loved institution by a government that hasn't had the courtesy to give them the fullest possible assessment of their potential impact."
But the government has accused Burnham of refusing to publish a risk assessment when he was health secretary in the last Labour government.
Speaking during prime minister's questions, David Cameron said this showed Ed Miliband was a "rank opportunist" and that Labour was "not fit to run opposition and not fit for government".
Miliband said the troubled NHS Bill was fast becoming the prime minister's "poll tax". There are suggestions that the NHS is starting to cost the Tories electoral support, with an ICM/Guardian poll on Monday showing Labour had gained ground.
Lansley told the Commons on Wednesday afternoon that if high level risk assessments were published then they would become "bland and anodine" as civil servants would be afraid to include anything too controversial. "They would cease to be of practical value," he said. "The publication of a risk register takes away and distracts form the purpose it is intended to support."
And he noted they were by their nature "devils advocate" documents that did not detail the positive impacts of any policies. He said Labour should read the impact assessment of the Bill as that looked at both the good and bad parts of the legislation.
Downing Street pointed towards Burnham's refusal to publish a risk register in 2009 following a Freedom of Information request. He said at the time: "Putting the risk register in the public domain would be likely to reduce the detail and utility of its contents."
"This would inhibit the free and frank exchange of views about significant risks and their management, and inhibit the provision of advice to ministers."
But Burnham told the Commons that he had turned down a request to publish the full departmental risk register not a specific one dealing with an individual piece of legislation, which was a different thing.
Fifteen Lib Dems have also signed an Early Day Motion calling on the government to publish the information, including Duncan Hames, a parliamentary aide to energy secretary Ed Davey. Downing Street has said it expects all PPS to vote against the Labour motion.
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