Mr Lansley clashed publicly with a vocal opponent of his health service reforms as he entered Downing Street on Monday for a summit to discuss the controversial changes.

But the Prime Minister has backed his colleague, despite an opinion poll showing a majority of voters were in favour of ditching the legislation altogether.

Asked if he would sack the architect of the reforms, Mr Cameron said at a Downing Street press conference: "I think Andrew Lansley is doing a very good job.

"I have worked with him for many, many years and I think he understands the health service better than almost anyone else in Parliament and does a very good job and he has my support."

Mr Cameron said reform "always involves argument", but he is confident the Government can win the arguments and show the changes will improve the NHS.

"I think it is important we stand back for a moment and try to explain again to people what it is we are attempting to do because I think the principle behind the reforms does actually have quite good support," he added.

"For years, people have said there is too much bureaucratic decision-making in the NHS, we want clinical decision making. That's what the reforms deliver."

Meanwhile, Education Secretary Michael Gove denied being one of the three Cabinet ministers reported to have expressed their concerns about the Health and Social Care Bill to the website ConservativeHome.

Mr Gove told a Westminster lunch he was "absolutely" in favour of the reforms contained in the Bill and praised Mr Lansley for being "brave and right and principled in pressing ahead with it". He added: "I do not think - and I have not said to anyone - that we should drop the Bill."