Changes to NHS reforms backed publicly by Nick Clegg in a bid to see off a Liberal Democrat grassroots revolt were drawn up with the help of Tory ministers, Andrew Lansley has told MPs.
The Health Secretary dismissed Labour claims that a letter issued yesterday by the Deputy Prime Minister and a leading critic of the legislation betrayed a Government in "disarray".
Responding to an urgent question in the Commons over the controversial Health and Social Care Bill, he repeatedly insisted that the coalition was entirely united.
Mr Lansley conceded that the amendments, set to be accepted tomorrow as the reform package continues its stormy passage through the House of Lords, were "significant".
That appeared to be at odds with statements by Downing Street yesterday, which had played down the impact of the changes backed by Mr Clegg.
But he insisted that they did not alter the fundamental nature of the reforms.
Nothing in the legislation as it existed would allow a US-style "market free for all" in healthcare, he said, but "further reassurance" could be given to opponents.
Competition elements in the legislation remain the most controversial with Lib Dems.
Granted a chance to grill Mr Lansley over the letter to Lib Dem peers and MPs - signed by Mr Clegg and Baroness Williams - shadow health secretary Andy Burnham said either the Government was in disarray or the letter had been carefully choreographed by the coalition to save Mr Clegg embarrassment.
Party activists are gearing up to take on the Lib Dem leadership over the shake-up at the party's spring conference - a year after a previous revolt there forced a "pause" in the Bill.
Both governing parties were "putting their political pride ahead of the best interests of the NHS", he suggested, questioning who was in charge of the policy.
Mr Lansley told him: "The point of the letter was to reflect the debates we've been having.
"We, and I do mean all of us on these benches, are using the debates in the Lords further to reassure all those who care about the NHS.
"The Deputy Prime Minister and Baroness Shirley Williams were explaining to their Liberal Democrat colleagues some of the amendments we have been working together on in order to make sure there is further reassurance."
He added: "The Bill is about quality, not competition on price. The Bill does not permit any extension of charging; care will be free and based on need.
"Where doctors and nurses on the ground know that competition is in the best interests of their patients, where it is based entirely on the quality of the care and treatment provided and not in any way on the price, then competition can play an important role."
Asked to clarify whether or not the changes were significant, Mr Lansley said: "The amendments... which we will support, will by their nature be significant."
The debate came as a committee of MPs ruled out a specific debate in the Commons of a petition signed by nearly 163,000 people calling for the Bill to be dropped.
Any such demand which secures six-figure support on the Government e-petition website is eligible for debate.
But the backbench business committee ruled that it did not have sufficient cross-party support and that the issue had anyway been extensively debated in Parliament.