David Cameron warned Tory activists that there could be no turning back to the policies of the Thatcher era as he put safeguarding the National Health Service at the heart of his efforts to return the Tories to power at the next election.
In an hour-long speech ending his first party conference as leader, Mr Cameron also took on critics who accuse him of lacking substance or policy, using the key issue of taxation policy as an example that they were wrong.
Tax has been the main battleground of the conference as rightwingers spearheaded by Lord Tebbit, the former party chairman, argued that Mr Cameron should pledge tax cuts at the next election.
"Substance is not about producing a ten-point plan. It is about deeper things than that," Mr Cameron said. "It is about knowing what you believe, it's about a clear idea of the Britain that we all want to see."
He added: "Everyone in this hall, me included, knows that a low-tax economy is a strong economy. But some people want me to flash up some pie-in-the-sky tax cuts to show what we stand for.
"Let me tell you straight: that is not substance and that is not what we stand for. Do you know what I think? I think that when some people talk about substance, what they mean is they want the old policies back.
"Well they're not coming back. We're not going back."
It was a speech aimed well beyond those in the hall - many of whom are uneasy about the party's shift to the centre ground and Mr Cameron's brand of touchy-feely politics - and which stole shamelessly Labour's policy clothes on issues such as crime.
Presenting himself as a committed family man optimistic about the country's future, Mr Cameron also took pains to make clear that public services would not be slashed under a Conservative government.
He devoted much of his speech to the message that the National Health Service would be safe under his government, implicitly linking his personal attachment to free healthcare to the fact that he has a severely disabled son.
"The NHS is vitally important to every family in this country - and my family is no exception, it's vital to us," Mr Cameron declared.
"I believe that the creation of the NHS is one of the greatest achievements of the 20th century. It is founded on the noble but simple ideal that no person should ever have to worry about their healthcare.
"But it's about more than that. The NHS is an expression of our values as a nation. It is a symbol of collective will, of social solidarity. That is why the British people, of all political parties and none, are so proud of it and so attached to it."
He added: "For me, it's not a question of saying the NHS will be safe in my hands. Of course it will. My family is so often in the hands of the NHS and I want them to be safe there.
"Tony Blair once told us that his priorities could be summed up in three words: education, education, education. I can do mine in three letters: NHS.
"We will serve and support the National Health Service, we will always support the NHS with the funding it needs, but we will make sure that the money is well spent."
The Conservative leader told his party that he would back successful Labour initiatives, such as Bank of England independence and the minimum wage, promising to increase it if possible.
But he then rounded on Tony Blair for giving up on Cabinet government and taking decisions instead around the sofa in his office at No 10.
"No notes are taken. No one knows who's accountable. No one takes the blame when things go wrong," Mr Cameron said. "That arrogant style of government must come to an end. I will restore the proper processes of government.
"I want to be Prime Minister of this country, not a president."
Heralding proposals for new green taxes, Mr Cameron said: "I want to tell the British people some uncomfortable truths - there is a price for progress in tackling climate change.
"Of course, low-energy light bulbs, hybrid cars - even a windmill on your roof - can make a difference and also save money. But these things are not enough.
"Government must show leadership by setting the right framework: binding targets for carbon reduction year on year. That would create a price for carbon in our economy.
Perhaps the loudest applause came when the Tory leader heaped praise on British troops fighting abroad in Afghanistan and Iraq, saying: "We should do more - a lot more - for them."
On domestic security and the terrorist threat, Mr Cameron promised that he would always listen to the police and security services.
"I will never play politics with this issue - what I will do is my duty, which is to support the Government when they do the right thing and hold them to account when they do the wrong thing," he said.
"So let me say plainly, I do think that this government is getting some things wrong. They're pressing ahead with ID cards that won't stop dangerous people coming into our country when they can't give us proper border controls that just might.
"They're bringing in new offences that aren't being used but they haven't changed the law so that wire-tap evidence can be used to prosecute terror suspects in court."
Mr Cameron repeated his pledge to repeal the Human Rights Act and replace it with a new British Bill of Rights.
He also laid into the Prime Minister on crime, saying that his "cheap joke" at last week's Labour conference about Mr Cameron's "hug-a-hoodie" meant that he had given up on "one of the best things he ever said - that we need to be tough on the causes of crime".
"Everyone in this hall, everyone watching at home, knows that we will only tackle crime in the long term if we tackle family breakdown, if we tackle drug addiction, if we mend broken lives," he added.
On foreign policy, the Conservative leader drew on his family past, saying his grandfather had taken part in the D-Day landings and he himself had become involved in politics during the Cold War.
"But now Mr Blair objects when I say our foreign policy should not simply be unquestioning in our relationship with America.
"Well, if he's accusing me of wanting to be a British prime minister pursuing a British foreign policy, then I plead guilty.
"Questioning the approach of the US administration, trying to learn the lessons of the past five years does not make you anti-American."
Rounding off his speech with a message of optimism, he told delegates: "We must not be the party that says the world and our country is going to the dogs. We must be the party that lifts people's sights and raises their hopes.
"We are getting ready to serve again. We're standing up for what we believe. We're reaching out for what we can achieve. So let us say here today, confidently, that for Britain the best is yet to come."
