David Cameron was forced to issue a vote of confidence in his Health Secretary, Andrew Lansley, yesterday as ministers search for an NHS reform blueprint acceptable to both parts of the Coalition.
There has been growing speculation over Mr Lansley's future since his plans to overhaul the NHS were dramatically halted by Mr Cameron and Nick Clegg in the face of a rebellion from health professionals.
The Health Secretary, who has spent years drawing up proposals to restructure the service, has made it clear he would quit the Cabinet rather than move to another post.
There were also reports yesterday that the Prime Minister would be prepared to accept his resignation on the grounds that a new face would be needed to make the case for the heavily modified plans.
A Downing Street spokeswoman dismissed as "nonsense" suggestions that he could be sacrificed, adding: "Andrew Lansley is doing an excellent job as Health Secretary."
The progress of the Health and Social Care Bill through Parliament was stopped last month as the Prime Minister ordered a "listening exercise" with the public.
The Bill abolishes primary care trusts, passes the vast majority of the health budget to family doctors and allows private companies to compete to run essential NHS budgets.
Its modified version, which is due to be published by the end of June, is likely to contain such sweeping changes from the original Lansley vision of the NHS that it could have to face extra scrutiny in the Commons, setting back the Government's planned timetable.
Ministers are expected to allow other professions, such as hospital doctors and nurses, to join the new commissioning bodies and to permit GPs to opt out of the plans if they prefer. But the detail of the revised proposals is still being argued over by Mr Cameron and Mr Clegg and their teams. Tory MPs are alarmed by signs that the Prime Minister is turning against his Health Secretary and is planning to amend the plans substantially, but party sources are more concerned that the Liberal Democrats could receive all of the "credit" for blocking unpopular reform.
Yesterday Liam Fox, the Defence Secretary, strongly defended the aims of the planned health reforms. "We need to get the outcomes of the NHS up, we have to get better health outcomes in this country for the money we spend. We also have to ensure that more decisions are taken by doctors and nurses. The question is how do we do that, not whether we have to do it," he told BBC1's Andrew Marr Show.