It is almost impossible to listen to the Today programme if you have young children these days. On some mornings recently I have found myself hitting the mute button repeatedly as details of one appalling case after another are discussed.

In truth it's not just the children I'm protecting. I could not bear to read the reports about Baby P - even the photographs of his blood-stained vest made me feel sick. The details of the Shannon Matthews case were heartbreaking. Incest, child-trafficking, ritual abuse, there is a new horror every day.

It is easy to see these stories as modern-day morality tales, a real life version of Heinrich Hoffmann's Struwwelpeter. Instead of the girl who played with matches and burnt to death, we have the woman who lived on welfare and sold her daughter's soul. Rather than the boy who sucked his thumb, and had it cut off with scissors, there is the social worker too busy box-ticking to spot the bruises on a child's body. In the place of boys dipped in black ink, we have the underclass, festering in poverty on sink estates as if its members will forever be marked out as different from the rest of society.

In fact, the cases that have been going through the courts recently are about bad people. They are isolated instances, that can no more be blamed on poverty than they can on the benefits system.

But there is something all these stories have in common - they are about bad people being bad parents. To the extent that there is a wider lesson to be drawn by the Government it is about how to improve the way in which people bring up their children.

Of course it is reasonable for Ed Balls to propose changes to social services departments - but social workers only get involved when something goes wrong. There must be more that can be done to stop it getting to that stage. As Frank Field has said, there is, in some parts of the country, a social crisis in parenting “every bit as dramatic as the economic recession we are now entering”.

This is, in fact, something the Government realised early on. One of Labour's first decisions, when it was elected in 1997, was to set up Sure Start, a programme designed to help parents, particularly those in deprived areas. There are now 3,000 Sure Start centres, combining child care, health advice, employment training and parenting support for 2.3 million families. Labour has promised to create 500 more by 2010 at a cost of more than £1 billion a year.

The early indications are that the programme is working. The National Evaluation of Sure Start research team, which is analysing 9,000 families in 150 areas, and comparing them with similar families in areas with no Sure Start scheme, has found improvements in everything from literacy to obesity, from behaviour to safety. In an article published in The Lancet last month, the team concluded: “In [Sure Start] areas children showed better social development, with more positive social behaviour and greater independence, and parents showed less risk of negative parenting and provided a better home-learning environment.”

The team is now assessing the impact on children as they progress to school. Professor Edward Melhuish, who heads it, says: “It would seem likely that the benefits we are seeing with three-year-olds will lead to better development later on.”

There is cross-party support for the principles of early intervention. When David Miliband was head of Tony Blair's policy unit, he used to say that children were “ruined by 3” and so the State had a duty to intervene before they got to school. More recently Tory frontbenchers have started citing research by Leon Feinstein, which found that bright children from poor backgrounds end up doing worse at school than more stupid children from wealthy families.

Sure Start is potentially Labour's great success story - a policy that could increase social mobility while stunting the growth of the underclass. But the Government is in danger of suffocating its own best creation. Most of the projects are now concentrated in large children centres that focus on day care, undermining the small independent local clubs. A new curriculum for the under-5s has put the emphasis in these centres on education rather than parenting - with targets for lego-building, Play-Doh proficiency and knowledge of nursery rhymes.

The funding of Sure Start (which originally came directly from Whitehall) has been given to local authorities, which are taking a much more politically correct approach. There is an increased emphasis on outreach activity, with funding linked to the number of children from poor families involved in programmes. Forms have to be filled in, with dozens of questions about the ethnicity, language and income of participants. In some cases parents are asked whether they have a garden for their children to play in. The objective is clear - to identify the middle classes. A friend of mine was telephoned by her local Sure Start organiser and asked not to come to baby massage classes any more because she was too posh.

The brilliant art club where my two-year-old learns to make spider's webs out of dried spaghetti and elephants from milk cartons (in the middle of one of Hackney's grimmest council estates) has had its funding cut because its clientele is not diverse enough. In fact, a complete mix of children attends - and that should be the point.

Of course it's important that Sure Start reaches the people it was originally designed to help. But it would be ironic if the policy designed to reduce social exclusion ended up building up class barriers in another way. It was, after all, social segregation that in part led to the fate of Baby P and Shannon Matthews. Middle-class parents send their children to Sure Start activities because they are good. It would be a tragedy if they were turned into ghettos for the poor.

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