Tony Blair has signalled that he would use a third term in power to radically alter the welfare state and further reform the public services.
Mr Blair argued big ideas still matter
"Bold" reforms were needed to create an "opportunity society" where working-class people could share middle-class aspirations, he said in a key speech.
The welfare state had to give way to a system where everyone got high quality services and the chance to succeed.
Big visions were still needed, he said, rebutting the latest Tory message.
The Tories say people no longer trust "grandiose" visions from politicians, and are promising "action not words".
Mr Blair attacked the Conservative stance directly in a speech to the Institute of Public Policy Research and Demos.
With its stress that there is much still to do, the speech is being seen as an attempt to show Mr Blair wants a full third term in office before standing down as prime minister.
It also trailed government proposals being published in coming months on a range of areas, including childcare, public health and adult skills.
Mr Blair said: "There is a sense in these days that it's better for politicians to reject grand visions and great causes and go for what the Tories have done, for what I might call minimalist politics - an offer so bare that its very paucity is meant to give it credibility.
"However, the big challenges facing the country will not be made by minimalist politics but by bold and far reaching reforms rooted in the values of fairness and social justice."
Mr Blair said he wanted to move from a welfare state offering basic public services and relief from poverty to one giving high quality services and the opportunity for everybody to realise their potential.
"The truth about the country is that for almost 30 years social mobility has stayed relatively constant," he said.
"I want to see social mobility, as it did for the decades after the war, rising once again, becoming a dominant feature of British life."
Mr Blair said the boldest reforms had brought Labour's biggest advances, but he has not unveiled new policies.
In a blunt message to left-wing critics, he said there would no retreat from New Labour's ideals or modernisation of public services.
There was a need to find new and imaginative ways of funding public services, he said.
He denied Britain was in decline, citing a record period of economic growth and employment.
Spending on "social failure" was down but it was right it had risen on pensions, child benefit and tax credits, he said.
Mr Blair also said punishment alone would not solve the long-term problems of drug and alcohol abuse and a "whole new national infrastructure" was needed.
A major pensions report is out on Tuesday
He reinforced this pro-reform message in an address to Labour backbenchers on Monday evening warning against complacency at the next general election.
"Whatever the polls or people say, the next general election will only be won
when it is actually won," he told a meeting of the Parliamentary Labour Party.
He also faced repeated calls for him to apologise for the Iraq war from Newport West MP Paul Flynn, but he brushed these aside insisting he had taken the right decision.
Turning to pensions, the prime minister said it was essential to move ahead by consensus as the pensions system could not stand regular upheaval.
People needed more choice about working and saving, including changing the culture where people were written off at 65-years-old.
Tuesday sees the publication of Adair Turner's interim report for the government on the future of pensions.
The Conservatives say the gap between rich and poor has grown wider since 1997 and policy co-ordinator David Cameron accused Mr Blair of being full of waffle.
He argued it was not minimalist simply to say head teachers should be able to control school discipline and police should be on the streets.
Invoking an advertisement for wood varnish, Mr Cameron told BBC Radio 4's World At One: "People are crying out for a kind of Ronseal politics - they want it to do what it says on the tin."
Liberal Democrat chairman Matthew Taylor said too much control from Whitehall was hampering public services.
"People are rapidly losing trust in the prime minister who endlessly relaunches his promises
but never actually delivers on them," said Mr Taylor.