Here are the names of those Lib Dems to sign the motion - backed by 75 MPs in total:

Annette Brooke (Mid Dorset and North Poole)
Mike Crockart (Edinburgh West)
Andrew George (St Ives)
Duncan Hames (Chippenham)
Mike Hancock (Portsmouth South)
Martin Horwood (Cheltenham)
Julian Huppert (Cambridge)
John Leech (Manchester Withington)
Greg Mulholland (Leeds North West)
John Pugh (Southport)
Alan Reid (Argyll and Bute)
Bob Russell (Colchester)

And an Opposition Day debate in the House of Commons on publication of the NHS risk register is now scheduled for 22 February.

Mr Morris said: "Our suspicion is that it identifies a cost surge and one of the Government's principle justifications for the Health and Social Care Bill is that this reorganisation will bring about the delivery of improved outcomes in a more efficient manner.

"Our suspicion is that the risk register suggests that may not be the case.

"There is an easy way for the Government to disprove that - just publish it," said the Easington MP, a member of the Commons health committee.

He added the document should be released now so that Parliament could debate its implications. "It could be the final nail in the coffin of the Bill," said Mr Morris.

The Government is appealing against a decision by the Information Commissioner, Christopher Graham, who ruled that ministers were wrong to keep the risk register under wraps.