David Cameron has unveiled changes to his party's stance on healthcare which he hopes will persuade the public the NHS is safe in Conservative hands.
Doreen Ingram takes Mr Cameron's disabled son to school
Mr Cameron ditched the previous policy of subsidising patients to go private and criticised Margaret Thatcher's tax breaks for private medical insurance.
In his first big policy speech since becoming leader he said he wanted the NHS to be free for all.
Health Secretary Patricia Hewitt said the Tories were in "headlong retreat".
"David Cameron has had to abandon a policy that he himself was putting forward just six months ago," she said.
Conservative: NHS "free at the point of use"; rule out medical insurance schemes; have more private sector involvement in NHS
Labour: NHS "free to all"; patients able to choose any hospital, including some private by 2008; limit of private sector doing 15% of NHS work; waiting times to be down to 18 weeks
Lib Dems: Policy review under way. At election wanted to cut diagnostic waiting lists for tests; free long-term care for elderly
Mr Cameron told the King's Fund think tank in London he had probably spent more time in NHS hospitals than almost any politician in recent years because he had a disabled son.
He wanted to remove any doubt about the Conservatives' commitment to the NHS.
Mr Cameron, who was in charge of drawing up the last Tory election manifesto, said he was dropping the party's "patients' passport" plan.
The scheme allowed patients to use half the cost of their NHS operation to be treated privately.
But Mr Cameron said it was wrong to use taxpayers' money to encourage the better-off to opt out of the health service: the NHS should not be something charitable or demeaning.
The Conservatives wanted to change the NHS into a more efficient, more effective and more patient-centred service, he argued.
"Other people - some of them in my own party - urge me to go much further," he said.
"They want me to promise that, under the Conservatives, the NHS will be transformed beyond recognition into a system based on medical insurance.
"I will never go down that route. Under a Conservative government, the NHS will remain free at the point of need and available to everyone, regardless of how much money they have in the bank."
Mr Cameron rejects such calls but also claims he would go further than Labour on reforming the NHS.
He said he wanted to give hospitals and GPs more autonomy, with more scope for private and voluntary sector providers to supply NHS services.
The government has said that by 2008 private sector providers will provide up to 15% of procedures on behalf of the NHS.
Outgoing Audit Commission chairman James Strachan has warned that, if the private sector accounts for 15% or 20% of NHS work, it will have implications for the remaining NHS services.
Karen Jennings, from the trade union Unison, which represents nurses and other healthcare workers, told BBC Radio Five Live that Mr Cameron was stating the obvious.
She said: "I think what we've got here is a bit of a bikini parade going on, you know, not a lot of clothes, not a lot of substance... I don't think we're getting anything profound here."
Liberal Democrat health spokesman Steve Webb said Mr Cameron's announcement lacked substance.
"What he's doing is ditching all policies with nothing really to take their place," he said.
Andrew Haldenby, director of think tank Reform, urged all the political parties to be more open-minded about medical insurance.
He said it was hard to see how an NHS funded only through tax could meet the costs of new drugs.