David Cameron is to mount a staunch defence of the government's welfare curbs, insisting they are at the heart of his drive to create a fairer Britain.
Setting out his vision for boosting social mobility, the Prime Minister will argue that the system must help people to get good jobs instead of giving them handouts.
But he will promise to balance benefit cuts with boosts to the minimum wage and personal tax allowance. He will also pledge further childcare support for working families, and improvements to education.
The keynote speech comes after Chancellor George Osborne and Work and Pensions Secretary Iain Duncan Smith confirmed plans to strip another £12 billion a year off the benefits bills.
The announcement, in a joint article for the Sunday Times, dashed speculation that the reduction could be scaled back or delayed.
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Labour leadership frontrunner Andy Burnham said it was "disgraceful" that ministers had yet to spell out where the cuts would fall and questioned whether they had a mandate from the electorate.
The shadow health secretary accepted that the welfare bill needed to shrink - but made clear he would oppose any effort to cut tax credits for the low paid or disability benefits.
He argued that tax incentives for companies to pay the living wage and housing market reforms would be more effective in slashing spending.
Mr Cameron - who has already ruled out any cuts to pensions or child benefit - will tell an audience in the north west that the country has been treating the "symptoms" of economic inequality rather than the causes.
"The right track is to recognise the causes of stalled social mobility and a lack of economic opportunity," he will say. "Family breakdown. Debt. Addiction. Poor schools. Lack of skills. Unemployment. People capable of work, written off to a lifetime on benefits.
"Recognise those causes, and the solutions follow. Strong families that give children the best start in life. A great education system that helps everyone get on. A welfare system that encourages work – well paid work.
"These are the drivers of opportunity – and we need to extend them."
The Tory leader will accuse Labour of being "complacent" about the issue of low pay.
"There is what I would call a merry-go-round. People working on the minimum wage having that money taxed by the Government and then the Government giving them that money back – and more - in welfare," he is to say.
"Again, it's dealing with the symptoms of the problem - topping up low pay rather than extending the drivers of opportunity – helping to create well paid jobs in the first place.
"We need to move from a low wage, high tax, high welfare society to a higher wage, lower tax, lower welfare society."
Mr Cameron will argue that the coalition began to "turn the tide on the failed approach".
But going further requires an end to "tolerance of government failure" and a defeatist attitude that says problems are "too big" to solve.
"The failure to look after children in care. The tolerance of sink schools that have failed one generation after another. An acceptance of long-term unemployment among hard-to-reach individuals," he will say.
"We have to end the complacency that has sometimes infected our national life, that says some problems are too big, and we can put up with second best.
"For me, when it comes to extending opportunity, the next five years will be about a complete intolerance of this government failure."
Mr Cameron will highlight three strands of his plan to improve social mobility.
Families will be strengthened will better childcare, flexible working and relationship support, as well as a faster adoption process and an expansion of the Troubled Families programme to help 400,000 families over the next five years.A focus on "first class" education, with "zero tolerance" of failing schools and a new focus on "coasting schools".
Creating well-paid jobs, increasing the the minimum wage to £6.70 in October and the personal tax threshold to £12,500 over the next five years and "going further" as the economy recovers and welfare is reformed.
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