Controversial changes to the NHS in England face further delay as MPs look again at the government's health bill.
Prime Minister David Cameron "paused" the reforms, which aim to hand control of budgets to GPs and to increase competition in the NHS.
But the scale of changes demanded by health professionals during the listening exercise look set to delay the bill even further.
Deputy PM Nick Clegg said it should be sent back for MPs to consider.
Following a speech on the reforms in London, he said the Health and Social Care Bill would need to be sent back to repeat its committee stage - effectively putting the Parliamentary process into reverse.
Mr Clegg said: "I don't think it would have been right for us to have held this listening exercise, to make big changes to this legislation and then seek to bounce it through.
"I think it is very important that MPs who are accountable to millions of patients up and down the country have the opportunity to really look at the details that we are proposing and that's why I think we will need to send the bill back to committee.
"I have always said that I think it is best to take our time to get it right rather than moving too fast and risk getting the details wrong."
The Department of Health insists the final decision on "recommitting" the bill has not been made.
Redoing part of the bill's Parliamentary passage could delay the timetable of reforms scheduled for 2012 and potentially risk the billions of pounds of savings that have to be made by the NHS by 2014.
The question, politically, is whether the changes will be radical enough to satisfy Mr Clegg and the Liberal Democrats without losing the substance of Health Secretary Andrew Lansley's original plans.
Number 10 has already said the reforms must continue.
All will become clearer when the government gives its response to the NHS Future Forum - expected in the middle of next month.
The Future Forum, made up of 45 clinicians, patient representatives and health staff, will hold their final listening event this week, leaving time for the group to thrash out its findings.
The media has not been allowed access to their meetings so as not to constrain discussions.
But the views of the group on three key policy areas are already clear:
- That the pace of change needs to be slowed down or at the very least varied across the country. In other words, no "big bang" as initially set out by Mr Lansley and a call for more piloting.
- That GPs alone cannot make decisions about commissioning. Other clinicians like nurses must be present on commissioning boards.
- That the role of the new economic regulator for the NHS must be clarified. Instead of just encouraging competition in healthcare provision it must reduce fragmentation and bring different services together.
The Future Forum will complete its listening exercise by the end of this week, but will continue to receive submissions from interested parties on Monday and Tuesday before drawing up its final report.
The British Medical Association, in its submission to the consultation, has said so much may need changing that the entire bill may need to be withdrawn.
Mr Cameron has insisted the NHS in England needs to change to avoid a "future crisis" as it was hobbled by too much waste, inflexibility and top-down control.
But critics of his proposals say they were not included in the government's coalition agreement and attempting a major re-organisation when the NHS is having to find billions in efficiency savings is foolhardy.
Shadow Health Secretary John Healey had urged the prime minister to send the bill back to its committee stage on Tuesday tabled a Commons motion for the recommittal of the bill.
He said: "I welcome Nick Clegg backing Labour's motion to send the Health Bill back to the House of Commons to re-run its committee stage.
"The government's plans for the NHS need to be radically rethought. If fundamental changes are going to be made to the legislation, they need full and proper scrutiny in Parliament."