Labour leader Ed Miliband has urged David Cameron to drop plans to overhaul the NHS, branding the government's flagship Health and Social Care Bill a "complete disaster".
But Mr Cameron accused the opposition leader of hijacking the debate on the health service to "try and save his leadership".
The leaders clashed over health reforms during prime minister's questions on 8 February 2012.
Opening his questions, Mr Miliband listed the organisations that have spoken out against the government's plans and asked the prime minister: "What went wrong?"
Mr Cameron hit back, telling MPs that 50 NHS trusts had publicly backed the overhaul, and citing former Labour MP Anne Campbell - now an NHS official - as one of its supporters.
Mr Cameron said he believed "passionately" in the future of the NHS, "not least" because of the care his family had received from the health service.
"I want to see that excellent service implemented for everyone and that means two things: it means we have got to put more money in to the NHS, and we are putting the money in, but it also means we have got to reform the NHS," he told the Commons.
The Labour leader fired back: "Even you don't believe that nonsense you just came out with."
He quoted the Royal College of General Practitioners as warning the reforms would cause "irreparable damage" to patient care.
Mr Miliband claimed the PM's promises to modernise the NHS were "coming back to haunt him", and suggested Mr Cameron thought he "knew better" than the doctors and nurses who "devote their lives to the health service".
But the prime minister defended the government's record, claiming there were more doctors and fewer hospital-acquired infections since the coalition came to power.
He told MPs that in Wales, where the NHS in run by a Labour government, waiting times had gone up.
The Labour leader continued his attack, telling the premier: "You know in your heart of hearts this is a complete disaster, this bill.
"Every day you fight for this bill, every day trust in you on the NHS ebbs away and every day it becomes clearer: the health service is not safe in your hands," he concluded.
Mr Cameron finished by offering faint praise for his health secretary, telling MPs that Mr Lansley's career prospects were better than the Labour leader's.
He accused Mr Miliband of attempting to save his own position, telling him: "This is not a campaign to save the NHS, this is a campaign to try and save your leadership."