Recently, it has been suggested that Alex may be called on to help police with their continuing investigations into his mother's murder, by looking at photographs of suspects. Because of his importance as a potential witness, Alex, with his father Andre Hanscombe, had access to the expert psychiatric care of a team at the Royal Free Hospital, London, which specialises in child PTSD, particularly in cases where a parent has been murdered in the child's presence.Now nearly seven, Alex lives with his father in France, and there has been no sign of post-traumatic distress disorder, say psychiatrists involved in his treatment. While many would recoil at this, convinced that it could only do him psychological harm, Dr Black says there is an argument for it. Talking about mummy is also vital to keep her as a real person for him; without this, other carers will replace her in his memories.That preventive intervention does work is evidenced by one of the most horrific murder cases of recent times, the stabbing to death of Rachel Nickell on Wimbledon Common one sunny July day four years ago. Her three- year-old son, Alex, was found clinging to her body, and so traumatised that he was unable to speak for sometime after the event. According to reports, Ms Lane had been behaving strangely and Steven had been heard by neighbours, screaming for hours on end before his abandonment in the park.

At age four, he would have been aware of the changes in his mother's mental state, according to Professor Morton. An explanation that "mummy wasn't well and the doctors were trying to make her better" would be something that had meaning to him. No one who saw pictures of the solemn-faced blonde, blue-eyed little boy last week, could doubt that he was suffering. Placed with foster parents whose brief, according to a spokeswoman for Dorset Social Services was "lots of tender loving care", and visited by his grandfather and other family members, he was described as "subdued and missing his mother desperately".The security a young child feels is intimately bound up with the safety of his mother or primary carer. Reassurance that his mother is now safe, and explanations of why she went away from him, will be the next stage. Younger children are often very affected by other people's response to their trauma, and will clam up if they feel someone else is shocked or distressed by what they are telling them, Mrs Gibson said, hence the need to create a secure and trusting environment to persuade them to talk about what happened.That is certainly the approach now being adopted with Steven Lane.

She describes that event as a "landmark tragedy" because of the deaths of so many very young children which was witnessed by their peers. Now in their early twenties, they are at least a year behind their peers in their studies, and fewer of them have gone on to university or obtained degrees. Julie Nurrish, a psychologist, said that the low uptake of psychological counselling and support - about 20 per cent - may have been a factor in the persistence and severity of the systems. The SS Jupiter sank in just 40 minutes after being rammed by a freighter in October 1988 Four people died, including a pupil and a teacher. Psychologists at the Institute of Psychiatry in London, found that one in 10 of nearly 200 survivors who were 14 or 15 at the time of the accident, had since attempted suicide, and more than half had suffered severe psychological distress. Overall, the survivors felt they could not plan for the future because their lives could be cut short at any time, Ms Nurrish said.Regardless of age, the foundation for effective preventive intervention is "love, comfort, and trust", according to Marion Gibson, a social worker with more than 20 years' experience in Northern Ireland and who trained some of the support workers now working in Dunblane, where 16 children and their teacher were slaughtered by Thomas Hamilton in March. Their reactions may be complicated by guilt that they were unable to stop something happening, or fantasies of revenge or retaliation against the perpetrator of a violent action against themselves or someone close to them.The devastating long-term effects of trauma if left untreated in this age group are apparent from a recent study of the survivors of a British school's cruise ship disaster.