Gordon Brown has told his party's conference they will fight the next election as New Labour.
Brown: To embark on UK tour
He said the UK must be a home-owning, share-owning democracy for everyone.
The chancellor's speech in Brighton is viewed as laying down his credentials to replace Tony Blair when he steps down ahead of the next election.
Mr Brown, who is to embark on a UK tour next year, said renewing New Labour would be as challenging as creating it had been in the first place.
Earlier Mr Brown said the succession issue was "for Tony Blair, it's for the Labour Party... I want to concentrate on getting on with the job".
But BBC political editor Nick Robinson said the speech was "more explicitly" that "of the next leader" than any other by Mr Brown.
The chancellor, who began by paying tribute to Mr Blair's leadership, spelt out his desire for a society with opportunity for all from the conference podium.
Mr Brown wants a "home-owning, share-owning, asset-owning, wealth-owning democracy, not just for some but for all".
'Party of reform'
Doing that, he added, will honour the party's constitution pledge of "putting power, wealth and opportunity in the hands of the many, not just the few".
And in a section which will risk angering some activists and union leaders already nervous about his pledge to continue Blairite reforms, he said: "When commentators tell you the next election will be old Labour versus new Conservatives, tell them the truth.
"The next election must and will be New Labour renewed against a Conservative Party today incapable of renewal.
"When they tell you that at the next election we will abandon reform, tell them that the Labour Party was founded so that our values could reform Britain, that the great Labour governments of the last century were great because they were reforming, progressive governments that transformed Britain and that the only future of the Labour Party is as a party of reform."
Mr Brown characterised the party's task as "finding modern answers, meeting rising individual aspirations - the new 21st Century individualism, while also - and this is the new 21st Century citizenship - showing how a supportive community can empower and enable people to realise their individual potential and make a contribution to community life".
His speech came amid some calls from unions and activists for the prime minister to hand over the leadership to Mr Brown sooner rather than later.
A number of senior ministers have made comments supportive of a Brown leadership.
Mr Brown told BBC Radio 4's Today programme that his spending plans were "perfectly affordable" but refused to "pin" himself to predictions about possible tax rises.
The economy was doing well, but slow growth rates elsewhere in Europe and high worldwide oil prices were adding to pressures, he added.
For the Conservatives shadow chancellor George Osborne said: "Gordon Brown told the Labour Party conference he was brought up to tell the truth. If this is the case then why was there no mention in his speech of the downgraded growth forecasts, massive budget deficit, record borrowing and the tax rises to come?
"Instead of masquerading as the leader in waiting he should get his own shop in order. Gordon Brown knows the longer he stays at the Treasury, the more his chickens are coming home to roost."