Ed Miliband is to appeal for voters to give him a chance to "rebuild Britain" as he kicks off Labour's conference.
Mr Miliband will seek to show he could govern the country more fairly by unveiling consumer-friendly policies including a beefed-up energy regulator.
Although Labour has been riding high in the opinion polls, the leader is under pressure to improve stubbornly poor personal ratings.
The Tories have highlighted the problem by releasing Populus research that found nearly two-thirds of Labour supporters would prefer Mr Miliband's brother David in charge. Some 73% of those questioned agreed that Mr Miliband did not have what it takes to be prime minister in tough economic times, and 72% that he was too weak for the job.
Mr Miliband will subject himself to more than an hour of questioning from all-comers at a town-hall style event in Manchester. He will blame David Cameron and the coalition for destroying people's trust in politicians, but admit that the challenges are "severe".
"Whoever wins the next election will be faced with a huge deficit," Mr Miliband is expected to say. "If it is a Labour government we will have to make difficult decisions. We will not be able to reverse all the cuts. We will take decisions about priorities like putting jobs ahead of pay rises. But don't believe those who say that all politicians are the same. Because our decisions will be different. We would always put the interests of millions of working people ahead of tax cuts for millionaires."
Insisting Labour is "on your side", Mr Miliband will pledge to replace Ofgem with an energy regulator that has tougher powers to ensure prices are fair. He will also propose capping pension fund management fees, amid complaints that people saving for their retirement are being ripped off.
"You know what it's like when the envelope hits the doormat with the gas bill or the electricity bill," he will say. "The companies know you can't choose not to pay it. They are making us pay more than we should."
Accusing the coalition of failing to protect pensioners, Mr Miliband will say: "Millions of working people are doing the right thing and putting money aside. The least they expect is for it to be there for them when they retire. But too often people are finding there is much less in the pot than they expected.
"What's been happening is while you were saving, the company which was supposed to be helping you, the company you trusted, has actually been taking thousands of pounds out in hidden fees and charges."