Iain Duncan Smith has vowed to rid Britain of the scourge of poverty and under-achievement.

The Tory leader, who has been criticised over his pledge to reduce public spending by 20 per cent, said he wanted to tackle rising crime, failing schools, sub-standard healthcare, child poverty and insecurity in old age.

"Those five giants already affect or threaten every community in Britain," he told an audience in London's East End.

"Defeating them isn't just a moral obligation. Turning the tide on crime and public service failure is in everyone's interest. Not just because none of us are immune from the damaging effects of social decline.

"But also because unless we come together as a nation - in order to advance the interests of everyone - we forfeit the right to call ourselves civilised. People from minority communities, our poorest citizens and the very young and very old remain Britain's most vulnerable - they are hurt most by the giants."

Duncan Smith conceded that Conservatives had sometimes given "the false impression that poverty had been overcome".

"During my leadership I've made it clear that that's not my belief," he said.

On education he pledged a new system of state scholarships to "give parents a chance to send their child to a good school".

"This system of scholarships will, I hope, encourage higher standards in existing schools," he said.

On crime, the opposition leader said he wanted to see a "greater emphasis on early intervention".

"And the Conservative commitment to fund 20,000 new drug rehabilitation places will give other young people a chance to find freedom from addiction," said Duncan Smith.

Pledging to build "a stronger, cohesive society" Duncan Smith pledged to harness community-based organisations to deliver change.

"By society I do not mean the state," he said. "The free institutions of society - like families, charities, local schools and other people-sized institutions - provide diverse, innovative and face-to-face care that state bureaucracies cannot match."

Duncan Smith said he would shortly set out his party's plans in detail.

"For a very long time the people-sized institutions of society have lacked political champions," he said.

"Their vital role has been taken for granted - or worse still dismissed - by big state and free market fundamentalists."

"That must change. Government can and must do much more to unlock Britain's social capital."

Duncan Smith said the "green paper" would contain proposals that are "as ambitious as the aspiration to serve of our nation's volunteers, charities and social entrepreneurs".

"That green paper will be a next stage in my party's continuing commitment to offer a fair deal for Britain's most vulnerable communities," he said.

"I look forward to as many of you here as possible helping us to first develop - and then deliver - that fair deal. It's time for politicians to help people rebuild their communities.

"And to return hope to neighbourhoods where - today - there is none."