An emergency debate will be held in the Commons on Tuesday afternoon on the government's refusal to publish the NHS risk register - a document detailing what the effects of Andrew Lansley's far-reaching reforms might be on the day-to-day running of the health service.
Lansley has refused to publish the dossier, despite rulings by the Information Commissioner and an appeal tribunal compelling him to do so.
The debate will come after the Health and Social Care Bill is expected to finish its long passage through the House of Lords, but before the Commons will vote on the amendments peers have made to the Bill.
Under a standing order of the Commons, shadow health secretary Andy Burnham said it was imperative that MPs had the full facts before them as they voted to pass the Bill into law.
"This is not a matter of the rights and wrongs of the Bill," Burnham told MPs on Monday afternoon. "Parliament has a right to know before it makes a final judgement."
The decision to allow the emergency debate came after Labour packed out its benches in the Commons and a visual gauge of the mood of the house was made by the Speaker.
Labour MPs cried "shame" to Lib Dem MPs Simon Hughes and Sir Menzies Campbell, who refused to stand up and be counted in favour of the emergency amendment.
Andrew Lansley was not present in the Commons at the time of the motion.
Peers will shortly start debating the Health Bill at Third Reading in the Lords. They have made a series of amendments to the Bill, but most of them have government support and came after Baroness Williams and Nick Clegg revealed a series of minor alterations designed to appease Lib Dems in the upper chamber.
Some amendments have not been approved by ministers, who are expected to try to overturn them when the Commons considers the amendments, following the emergency debate tomorrow afternoon.