A Tory government would plan to cut taxes - but would not make promises it could not keep, shadow chancellor Michael Howard has said.
Howard: Tories must learn lessons of Labour 'failure'
In his keynote speech to the Conservative conference in Blackpool, Mr Howard said the Tories would always be a lower tax government than Labour.
But he pledged that the party's plans would be carefully costed and not derailed by "overhyped rhetoric and overblown promises".
Mr Howard said a Tory government would provide an alternative to Labour's "tax and fail" by giving "power to the people" through its policies on education, health and other areas.
And amid talk of plots against Iain Duncan Smith - with Mr Howard suggested by some as a possible future successor - he offered strong backing to the Tory leader.
He said under Mr Duncan Smith the Conservatives were showing "the commitment, the drive and the determination" to put the party's ideals in practice.
Describing the government as "deceitful, dishonest and discredited", he said there were lessons for the Conservatives from Labour's time in office.
"Lessons on how we should approach government. Lessons for us in opposition too. Lessons we've learned under Iain's leadership.
"He and I know we must only make promises we can keep. Only pledge what we can deliver."
Mr Howard said voters were "fed up" with Labour's "endless tax rises, endless promises and failure to deliver".
He went on: "Let me make one thing clear: we believe in low taxes. We are the party of low taxes. All our instincts are fow low taxes."
He said people had been "hammered by higher taxes" under Labour.
He said: "We know that people have worked hard for their money and that governments must spend it wisely.
"We can and we will reform public services. We will always be a lower tax government than Labour. And we do plan to cut taxes.
"But unlike Labour's, our plans will be carefully costed. And unlike Labour's they will be clear for all to see."
Mr Howard gave no details on how the Tories would cut taxes, with aides saying the party's plans would be set out after next year's Budget and government spending review.
Earlier this week, Mr Duncan Smith vowed that the Tories would tax people less than Labour if they won the next general election.
The party leader claimed the goal would be achieved by cutting "bureaucracy and waste" in public services.
Responding to Mr Howard's speech, treasury chief secretary Paul Boateng claimed the Tories were committed to cutting public services and privatisation.
He said Mr Howard had said the Tories would not commit themselves to follow Labour's spending plans - and that would mean cuts in public services.