TACKED on the wall by Jean Harris Hendriks' desk, is a child's drawing of a face with spiky black hair. It is not the most flattering portrait, but the message written below it leaves no doubt as to the artist's sentiments. 'For the trouble doctor. Thank you for your help.'

Since 1987, Harris Hendriks and two other child psychiatrists attached to the Royal Free Hospital in north London - Dora Black and Tony Kaplan - have made a speciality of being 'trouble doctors' to children with one thing in common. All have lost one parent at the hands of the other.

Uxoricide barely rates a mention in our literature of passion, yet it is hardly a rare occurrence. 'This kind of murder is much more common than you think,' she says, 'and it happens in all social classes.' The Royal Free team has seen 200 children from 70 families.

The results of their seven- year study will be published next week. When Father Kills Mother (Routledge, pounds 12.99) is a disturbing but surprisingly readable book.

'We didn't choose the subject; it chose us,' says Harris Hendriks. 'We had a run of two or three of these cases. In each the children had witnessed the crime and were severely dislocated. Very little work had been done on this, and our study grew and grew.'

As a social crime, uxoricide poses very particular problems. Usually, it involves young parents. Eighty per cent of the children treated are under the age of 10. Often they are witnesses to the crime, or at least within earshot of it happening.

Invariably, they lose both parents, as the perpetrator is arrested or commits suicide, and are suddenly removed from their homes. During the trial, the victim - almost always the mother - is often denigrated as part of the defence. Relations between the two families break down, and the children are trapped in the middle. 'From every emotional and practical point of view, these children are as much refugees as if they came from Bosnia,' Harris Hendriks says. 'They have lost their homes, routines and their primary carers. They are violently disturbed.'

The problems of treating post-traumatic stress disorder are well known. The key to recovery lies in unlocking deep- seated feelings in such a way that the child feels able to confront its fears and come to terms with what has happened.

Relatives are often the greatest obstacle. Although full of good intentions, they can confuse an inability to come to terms with their own grief with what they consider to be best for the children. 'Again and again, we encounter the myth that children are too young or that they forget.'

Harris Hendriks recently saw an 18-month-old child who had been asleep in a house where its mother was murdered, and who showed all the physical reflexes of a six- month-old. She put the regression down to trauma. 'We must assume that children can be affected at any age.'

Children who are too young or too shocked to talk about their fears are encouraged to use drawing, toys and playing to express themselves. As a result of the Lockerbie air crash and the Zeebrugge ferry disaster, this therapy has become widely used in Britain. What is far less often understood is how much help is needed by the adults.

'The most common pattern is that the father kills the mother, but refuses to plead guilty to murder. Instead he offers to change his plea to manslaughter and receives, typically, a five-year sentence, which with model behaviour finds him parolled after serving only two years.

His children will be sent to live with relatives, often the victim's, which the father goes along with while he is in prison.

'When he is released all that is thrown up in the air. Often, he will be released without the family knowing. Then he will expect the children to uproot themselves once more and live with him.'

The father's release is often the hardest time of all. The victim's relatives find themselves overwhelmed by anger and grief that the mother - their daughter - is dead while the murderer is alive and free. This is the moment when relations between the two families are most likely to break down. 'Imagine if Othello and Desdemona had had a baby, and you have some idea of what we're dealing with.'

Harris Hendriks believes that the current legislation, with its emphasis on less intervention by the authorities, leaves a lot to be desired. She she would like to see children being more protected by the state, and the wardship of children reinstated.

For the Royal Free team, working with the adults is as important as working with the children. Supporting relatives and social workers by alerting them to the dangers of denial or helping them cope with difficult times, such as the trial, anniversaries, visits to the father in prison or his release, not only helps the adults concerned but is often the best way of helping the children. Little wonder that it is both the children and the adults who call the Royal Free team the 'trouble doctors'.

(Photograph omitted)