If I tot up the number of vulnerable children who I've met in recent years in my role as a journalist there are well over 50 of them, and it's strange how many of their faces I remember. Not necessarily their names - I always change them for publication - but the faces, they stay with you.

There was the 14-year-old burglar who said that he'd rather stay in a secure establishment than go back into care. Locked up, he felt safe. He pointed out that he had nothing to look forward to and when I asked how he saw his future he replied with one word: "Prison." He begged for a mention, but didn't believe I'd honour my promise to write about him because people always let him down.

Many of the boys - especially boys - were desperate for attention, even from someone they didn't know. Others had shockingly bleak faces and couldn't communicate. There were twitchy children who couldn't sit still, lots of them. Recently I met a bright, fizzy 12-year-old who hungered for conversation but didn't know how to sit down.

Then I read about the two boys charged with the attempted murder of two of their peers in Edlington, near Doncaster. And even though I'm a mere observer in the field of working with damaged children, I was reminded of the forces that affect those I've met.

No matter where vulnerable kids live in Britain, the themes that surround them are always the same. Many are the obvious motifs sent up by Little Britain, and are no less accurate for that: deprivation, single parents, feckless single parents, absent fathers, parents in prison, drug and alcohol misuse.

The most pervasive circumstance is delinquent and neglectful parenting. Sometimes the parents know that they are harming their children, sometimes they don't know how to be parents. Most of the children who turn to antisocial behaviour have been abused in their homes, either emotionally, physically or sexually. The manager of a secure children's home told me that few of the children under her care - and the kids there are lucky because she does care - had heard the word "no" from their parents. At best discipline is ambiguous, at worst there is none, with the result that these children have no concept of the connection between cause and effect. So not only do they fail to see the big picture - if they don't go to school, they won't become educated and stand a chance of getting a job - but they don't grasp what's going on here and now either. They know that stealing will get them something they want, but the other consequence - that someone else will be hurt by the theft - doesn't register.

This week I asked a child of 10 or so to move to a window seat on a busy bus so that I could sit down. He did so with obvious irritation. Then I realised that his dad was sitting behind us, also taking up two seats; the child was copying his father's behaviour. Why was there no consideration for other people? Presumably because no one had encouraged the dad to think that way so he had no social awareness - or indeed social skills - to pass on. The incident was tiny, the implications monumental.

Talk to the parents of vulnerable children, who are usually poorly educated themselves, and you will pick up something else: a moral vacuum in which responsibility lies elsewhere. When the kids are at school, the school is responsible for their behaviour, they tell you. What can they do? Not their fault if the kid gets in a fight. Yet the chances are that at home there is no structure, there are no barriers to tell a child where the line lies between acceptable and antisocial behaviour.

There is more likely to be chaos. Domestic violence is common, and so are mental health problems. Add to that a culture where it is normal for families to live on benefits and it is easy to see that families can lack motivation. If adults who earn money through paid work are a rarity, then the role models with ready cash - the achievers, if you like - are the drug dealers in their powerful cars, or the controlling gang leaders.

What comes out of all this is a sense that there is no hope, no legitimate future worth striving for. Worse, now that the cycle of deprivation, abuse and neglect is being repeated by a fourth generation, children grow up with low self-esteem and an expectation of failure. I have lost count of the number of young people I've met who told me that their parents and their teachers had told them they were useless. Programmed to fail, that is what they did. Yet it is rare to hear these children criticise their mothers. Boys especially are loyal; they seem to sense that their mothers want to care even if they don't know how.

It is easy to make these bleak judgments, much harder to change children's values and outlooks. There are some fine professionals in this field who admit that however wrong it might seem to lock up children for a couple of years, this can be the only way to help them. Nurture a damaged child for six months, chuck them back into the corrosive environment from which they came, and they are likely to re-engage immediately with the forces that hurt them. Work with them for two years and you stand a chance of making a change. Professionals need time to show failing kids that they have strengths, to give them a sense of pride and achievement - and often to work simultaneously with their families.

The professionals who are most impressive are invariably people with warmth who instinctively know that what will save these kids is a relationship with a caring adult. Last year I visited Thorn Cross young offenders institute where a wise prison officer had started a mentoring scheme. She reasoned that young people in prison would benefit from being given responsibility, and would cope with it provided they were supported by her staff. As a means of giving teenage boys confidence and social skills that will help them on release, the scheme has been successful - and costs nothing, I was told.

That explicit combination of emotional intelligence, kindness and sheer warmth should be the bedrock of all the work that is done with vulnerable children. Yet you won't find it in a report or a job description. Why not?