The Tories will become the party that represents working people rather than the rich and powerful, David Cameron has said in his New Year message.
David Cameron reflected on his first year in charge
The Tory leader also promises that next year his party will set out its alternative policies in more detail.
He warns that 2007 will be the year "Labour's dark side comes to the fore".
Shadow home secretary David Davis said he will head a new Tory taskforce, which the party says will study how to reverse a decline in social mobility.
Writing in The Sunday Times he said the tax and benefits regime, business red tape and failings in education were responsible for holding people back.
"A youngster born into the bottom quarter of society half a century ago was more likely to get on and work their way up to a higher economic class than those making their way today," he said.
Mr Cameron said that Gordon Brown taking over from Tony Blair would usher in "an onslaught of negative campaigning and the politics of fear and division."
The "real battle for Britain's future" would begin next year, he said.
"2006 was the year in which the Conservative Party moved back into the mainstream of British politics - a modern, compassionate voice for change, optimism and hope," he said.
"In 2007, we must move into a new gear - setting out in detail our clear, positive alternative to a Labour government whose incompetence and untrustworthiness is beginning to disgust the working people it was elected to serve."
Mr Cameron was responding to criticism that the party lacks policies.
Working people "want something done about the cost of living," he said.
"Council tax and utility bills keep going up and it's becoming harder for families to make ends meet."
He warned that Mr Brown would "pile on the pressure with still more tax rises".
"We must show that unlike Labour we will be a party that is for working people, not rich and powerful vested interests," he said.
The Tory idea of "social responsibility" would make life better than Labour's "state control", he added.