In recent years I have spent time visiting hard-pressed communities across Britain, hearing first hand about the problems people face. Broken and dysfunctional homes which too often leave their children with poor life chances, sliding into violent street gangs, drug and alcohol abuse.

In every area life is getting worse. Drug and alcohol abuse, worklessness, family break-up, failed education and debt run through these people’s lives like a rough thread, creating a vicious cycle of deprivation. As the welfare society retreats, it leaves growing numbers dependent on the state and as social mobility grinds to a halt, the results are starkly evident.

Perhaps unsurprisingly, these five pathways reinforce each other. Children who have suffered family breakdown are 75% more likely to fail in education and are far more vulnerable to poor mental health and addictions. People with a history of drug or alcohol addiction are more than twice as likely to have experienced personal debt as the general population. Almost 11m people in Britain today suffer from relationship problems as a result of debt. Two-thirds of young offenders are hard drug users.

A third have been in care and half have no qualifications.

Last month the prison population reached 80,000 for the first time. In 1993 the number incarcerated was just 45,000. While changes in sentencing policy are partly responsible for this steep rise, it also reflects government failure to tackle the social breakdown within which crime thrives.

Do not misunderstand me, poverty never excuses criminal behaviour and most who grow up in deprivation abide by the law. But the fact remains that the worsening of many social problems means that many more young people find themselves on a conveyor belt to crime. In the past few days the government has admitted it is missing its drug and crime targets. We wonder, as we listen to yet another “bang them up” announcement, whatever happened to “tough on the causes of crime”.

I think of Simon, the leader of a community group that seeks to get long-term offenders rehabilitated. He summed up his work by the story of John, a typical and prolific offender.

John was raped at the age of five by one of his mother’s boyfriends. No one did anything about it and he carried the shame and guilt into his teenage years. With no support for his schoolwork at home from a dysfunctional family, all he took back to school each day was his anger and frustration. Exclusion followed, as well as cannabis, heroin and then drug dealing to meet the cost. Eventually the criminal justice system wrapped its arms around him and a life of prison alternated with hopeless dependency. “This,” Simon said, with a sigh of resignation, “is pretty normal.”

Yet such dependency seems to be growing. The government has spent vast sums on tax credits and benefits — the social security bill has risen since the mid-1990s by £35.5 billion during a period of economic growth and growing employment. Part of this cost was to lift those just below the poverty line of 60% of median income to just above it. However, the government appears to have forgotten about the most vulnerable. Our report shows that 750,000 more people have incomes below 40% of median income than a decade ago.

Furthermore, persistent long-term poverty is just as bad. A child from a family in poverty today is less likely to rise to the top of the income scale than a child in 1970. The increasing gap between those in severe long-term poverty and the rest of us has depressing implications for the future health and cohesion of our society.

Even those who win promotion or salary increases can face marginal tax rates of up to 90%, leaving a large section of society with little incentive to better itself.

There is also a fundamental lack of honesty and courage in the political debate. Family breakdown is a major cause of social exclusion. At the heart of this are high levels of break-up for cohabiting couples with children. One in two will have split by the time the child is five compared with one in 12 for married couples.

Yet for years this debate has been stifled — some government research papers even exclude marriage as a special family category. Small wonder that the cost of family break-up grows, estimated at £20-£24 billion. There is no attempt to get ahead of the cycle and the political class seems fearful about confronting the consequences of breakdown.

A similar problem is apparent in drug treatment. Vast numbers of drug addicts are desperate for access to the residential rehabilitation that would give them the best opportunity to get clean and stay clean. But half the nation’s rehab beds lie empty because of a funding crisis. Most addicts are offered substitute prescriptions and are then ignored. We have forgotten that they have children and other relations whose lives are torn apart by their addiction.

Breakdown Britain, the interim report of the Conservative party’s social justice policy group to be published tomorrow, lays bare the extent of the failure to tackle the causes of deprivation. It also shines a light on those remarkable small community groups from whom a sensible government could learn about the way to tackle this breakdown While the level of poverty may be measured by money, the causes are so often structural. This report seeks to create a better understanding of these causes. After all, poverty and deprivation are too important to be left to a stumbling Labour government which forgot to be “tough on the causes of crime”. Iain Duncan Smith