One million people who are fit-to-work have been on benefits for three years Report to be published by Work and Pensions Secretary Iain Duncan Smith Ministers under fire for capping benefits at £26,000 a year per household Study found a third of all children are not living with both birth parents By Tim Shipman, Deputy Political Editor One million people who are fit to work have been claiming out-of-work benefits for three of the last four years, according to figures released today. A report to be published by Work and Pensions Secretary Iain Duncan Smith will reveal that more than four out of ten work-related benefits are claimed by the long-term unemployed. The report will fuel controversy about welfare spending at a time when the Tories are imposing restrictions on what people can claim in state handouts. Welfare spending: More than four out of ten work-related benefits are claimed by the long-term unemployed, according to a report due to be published today Ministers have come under fire from Labour for capping total benefits at £26,000 a year per household and forcing those on Incapacity Benefit and its replacement Employment Support Allowance to undergo health tests to assess their readiness for work. The report says: "On 31st March 2012, there were 2.3 million claims for benefits that indicate a capacity for work or work-related activity. One million of those were from people who had been claiming one or more of the main working-age benefits for at least three out of the preceding four years. According to the Office for Budget Responsibility, social security spending will rise from £180billion this year to nearly £198billion in 2017/18. Work and Pensions Secretary Iain Duncan Smith said the figures showed that bringing in charities and private firms to help families with little history of work was the right move The report, published to mark the first anniversary of the Government's social justice strategy, also lays bare shocking figures about family breakdown. Two out of three children aged 12 to 16 in low-income households are no longer living with both their birth parents. By contrast, more than six out of ten children in middle to high income households are living with their parents, while just 39 per cent are not. In total, around a third of all children are not living with both birth parents. The report concludes: "Children growing up in low income households are twice as likely not to be living with both birth parents as children in middle to high income households." The study - Social Justice: Transforming Lives - also says that thousands of parents who fear family breakdown have used couples counselling. The DWP says local authorities have already turned around the lives of 1,675 troubled families. The report also looks at the gap in educational attainment between rich and poor pupils. In 2011-2012, 16.8 per cent fewer pupils on free school meals achieved good grades than those who were better off. The social justice strategy set out a series of targets to tackle the root causes of disadvantage, including family stability, worklessness and drug and alcohol addiction. Mr Duncan Smith said the figures showed that bringing in charities and private firms to help families with little history of work and to assess people for their fitness to work was the right move. He added: "This approach starts with the family - the foundation of our society. We are prioritising children's formative years and supporting strong, stable family relationships which we know offer children the best start in life.