The Government's controversial health reforms have survived the first of two last-ditch challenges in the Lords.
A bid by SDP founder, now independent crossbencher, Lord Owen to delay third reading of the Health and Social Care Bill was rejected by 328 votes to 213, Government majority 115.
Lord Owen wanted the delay to allow time to consider the reasons for publishing a confidential risk assessment of the reforms and the Government's response.
He denied this was an attempt to block the legislation and warned ministers they had "no mandate" for the NHS changes in England.
But health minister Earl Howe said delay would put into "serious jeopardy" work done by peers in changing the Bill over weeks of detailed scrutiny.
"Delay would be wrong and wholly unwarranted," he insisted. "The NHS needs certainty - the certainty of the Bill being on the statute book."
Later, in another rarely-used procedural manoeuvre, Labour will try to block the Bill's third reading and passage back to the Commons for consideration of Lords amendments on Tuesday.
An amendment put down by the Opposition urges peers not to allow the Bill to pass because it will "lead to the fragmentation and marketisation of the NHS and threaten its ethos and purpose".