The prime minister has been accused by leading doctors of making false claims about their level of support for the Health Bill.
Public health experts, who wrote an open letter to the House of Lords last week on the issue, said David Cameron was wrong to say they backed the Health and Social Care Bill.
In the letter, more than 400 public health doctors, specialists, and academics from across the country said “the proposed reforms will disrupt, fragment and weaken the country’s public health capabilities”.
Speaking to the BBC as it was published, Mr Cameron said: “When you look at the letter itself, it actually praises the part of the bill that’s about public health.
“Because we’re saying public health - smoking cessation, diet, dealing with things like diabetes - these are incredibly important and they welcome that part of the Bill.”
Health secretary Andrew Lansley also claimed experts had signed without reading it and it was “politically motivated” and unsupported by “a shred of evidence”.
But writing today in the British Medical Journal, several of those experts said: “These claims were wrong.
“There was no qualified support for the bill. Nor did signatories write in a political capacity: they wrote in their professional capacity and with the public interest in mind.
“Nor are public health professionals alone in having concerns: the public, the British Medical Association, and many of the royal colleges continue to express deep and continuing concerns.
“Public health professionals are responsible for assessing the healthcare needs of the entire population.
“This entails looking across the entire health system to ensure that its different components come together efficiently, effectively, and fairly.
“They are expected to speak out as advocates for the population and especially for those people with poorer health outcomes.
“But more importantly, our concerns are based on a wealth of evidence, much published in peer-reviewed journals.”
The experts go on to say there are many problems with the bill.
“For one, it abolishes direct accountability of the secretary of state for health to secure comprehensive care for the whole population and the mechanisms and structures for securing that duty.
“The health secretary has also stated that equitable resource allocation will no longer be his direct responsibility and that national resource allocation formulas will change from area-based populations to GP registrations, a move that portends a shift towards a model of competing insurance pools or funds, for which the evidence from other countries is adverse.”