The social exclusion minister, Hilary Armstrong, explained it in a letter to Tony Blair this week: “Our research is showing that early intervention saves individuals from the hardship of social exclusion and multiple problems later in life, and is cost-effective.

“We have strong evidence on those factors which place children and families at greater risk of experiencing difficulties and this information can be used to better identify those who need greater levels of support. What is more, there is strong evidence about what works best with these groups.”

As well the Prime Minister knows — for the move to target the most socially excluded children is being driven by him. It comes against the backdrop of the introduction of the national children’s database next year. This register of all children in England and Wales will record name, address, date of birth, gender, a unique ID, contact details of parent or carer, school, GP practice and other practitioners dealing with the child. Any health visitor, social worker, doctor or teacher who has concerns about the welfare of a child can flag it up — not the details of a worrying incident, but simply that there might be cause for concern.

Any subsequent person in authority who is worried about the child will be able to see the flag and call the professional who posted it to find out more. To ministers it is an important new protection for children designed to prevent a repeat of the Victoria Climbié abuse scandal. To critics it is an expensive and unworkable intrusion of the State into the home, which “sidelines the rights of parents to bring up their children as they see fit and amounts to a ‘ bar-coding’ of youngsters”, as one Daily Mail article (“Big Brother database to record the lives of all children”) succinctly put it.

And that’s not the half of it. What ministers now plan to do is to intervene before a child is born. Midwives will be trained to spot signs of family pressure in a mother and call for help, whether she has asked for it or not. The idea is to identify before birth the children likely to be born into disadvantage and family breakdown, and help the parents to cope.

Research conducted in New Zealand and adopted by the Cabinet Office here shows that children born into what ministers call “real deprivation” — deep poverty and dysfunctional parenting — are 100 times more likely to experience multiple problems such as drug and alcohol use, teenage pregnancy, crime and antisocial behaviour at 15 years old as children born into the “top half” of social advantage.

Leaving it until they reach school to try to help is too late: the most effective intervention takes place before a child is 3 and conveys positive traits such as empathy (the single greatest inhibitor of violence), which some parents fail to teach. A parenting scheme that brings together six parents to discuss their problems might cost £800 per child. Or for a few thousand pounds you can twin one professional with one family to visit every week until a child is 2. But head off a teenage pregnancy 12 years down the line and you have saved the £60,000 that each one costs in the first five years.

Ministers’ next problem was how to find the families most in need of help. Identifying them isn’t too hard. Keen not to stigmatise children, the Government will not publish “those factors which place children and families at greater risk”, but they are, unsurprisingly, poverty, drug or alcohol abuse by parents, parental mental health problems, teenage motherhood, domestic violence and having a parent in jail. Yet your likelihood of seeing a health visitor after giving birth actually decreases with your income; the people who most need help are those most likely to be left behind. Pretty much every mother, however, no matter what her income, sees a midwife; hence the co-option of midwives into the fight.

In part this is a story about the failure of new Labour. These are the people who have been left behind. If you look at the bottom 20 per cent of society in income terms, just 15 per cent of those have had some sort of significant help such as the New Deal, Sure Start or tax credits. But people not in work at all, and perhaps in the second or third generation out of work, have not formed part of the new Labour “project” and these are the ones the Government is now targeting for help. And it is about help. Ministers are desperate not to sound condemnatory; they emphasise that this is about providing opportunity, not preventing crime.

But it’s also about something else: the programme is naturally going to identify children most at risk from bad parenting. And for parents weaned themselves on tales of overbearing social services departments armed with their moral certainties, and the frighteningly powerful and secretive family courts, that is a real threat. I wonder whether it hasn’t occurred to ministers that the reason the poorer and most deprived families have so often proved beyond the reach of health visitors is because they are afraid of being reached.

A friend of mine has a child of nearly 3 who broke her arm last week. She told me quite matter-of-factly that she was glad it happened at a relative’s house and not hers because she had taken her daughter to A&E once before and, “you know, if you do it too often they call social services”. That is how frightened of the State parents have become. Those families that ministers want to find will be less afraid of being stigmatised than of losing their kids. And until ministers learn that not everyone shares their comfortable view of a beneficent State, I wonder how many of that bottom fifth they are ever likely to reach.

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