Fuel duty will be frozen until 2015 if the money is available, George Osborne has pledged as he addressed the Tory party conference.
The Chancellor’s pledge came as he warned the battle to rebuild the UK economy is not over and that the Tories must be allowed to finish the task.
Mr Osborne accused Labour of making up policy “on the back of a fag packet” as he addressed the Conservative Party Conference.
He warned of disaster if Ed Miliband was to win power, suggesting his eye-catching energy price freeze plan would stunt growth and cost jobs.
Countering accusations of complacency about the recovery, Mr Osborne insisted there was “no feeling of a task completed or a victory won”.
It was “not even close to being over and we are going to finish what he started,” he declared, insisting his policies were a “serious plan for a grown-up country”.
In his speech, he also unveiled tough new rules to make the long-term unemployed earn their benefits by doing full-time unpaid community work from next year.
From April, people still without work after two years on the coalition’s Work Programme will face three options if they want to remain on the dole.
They will have to do community work such as litter picking, visit a job centre every day or take part in compulsory training to tackle problems like illiteracy.
Those who break the rules of the new Help to Work scheme, for example by failing to turn up without a good reason, could lose their benefit for four weeks.
A second offence would see them lose it for three months.
Ahead of his address, Mr Osborne insisted on Sky News that the policy was not a return to the Conservative “nasty party” of old – describing the move as “compassionate”.
“This is not about punishment, this is about help,” he stressed, but also said: “What we are saying is there is no option of doing nothing any more.
“We are saying we are going to help you into work but we are going to ask for something in return. I think it is a very compassionate approach to people who previous governments just ignored.”