Margaret had two children taken away at birth. She says: 'My mother did it without me knowing. I never forgave her. I had bought everything for them but she just decided to get them adopted.' Margaret doesn't remember how old she was at the time, just that she was 'too young and the father buggered off'. The reason? Margaret, now 31, has learning difficulties. In America, Margaret would be described as 'mentally retarded'.

Four years ago, Margaret was made pregnant by her partner, Martin, who also has learning difficulties. A health visitor making routine visits was alarmed by the baby's failure to gain weight. Baby Lisa was admitted to hospital two pounds below her birth weight. Her parents didn't wake to feed her at night because, they say, she didn't cry.

By now social services were involved and Margaret was assigned a family aide to help her but Martin, a big man, was enraged by what he saw as interference and, within months, had sent them packing. 'I speak my mind,' he said. 'I told them where to go. They threatened to take her away and I said: 'You try it. You won't be walking out of here.'

Margaret was now having difficulty weaning her baby and Lisa's weight again began to drop. It seemed as if history was about to repeat itself. But fortunately she lives in Cornwall, the first county to give structured support to parents such as Margaret.

The Special Parenting Service is a division of Cornwall's Learning Disabilities Trust. The key to its success is its recognition that people who feel threatened are often unable to ask for, or use, help.

Clearly, in Margaret and Martin's case it is working. With support from 'trainers', who visit them regularly, they are now caring for a second baby, Nicola.

When I arrived at their little white-washed house in Truro, Margaret was busy hoovering - something which, judging by the general state of disarray, was being done in my honour. Seven-month-old Nicola, sitting on her father's knee, bouncing and beaming, was clearly thriving. There was no sign of under-nourishment here, even though the assistant psychologist from the SPS team made a point of checking on her feeding times.

Margaret had been given a leaflet, with specially commissioned illustrations, to remind her of the weaning instructions she has been taught, so that she doesn't have the same problems with Nicola that she had with Lisa. Lisa, now a shy four-year-old, has been to special classes to provide the stimulation she may be missing at home and has just started school.

Seeing Margaret with her baby it is hard to imagine that someone had to teach her how to copy her baby's gurgles; train her to encourage language skills; to explain to her the importance of praising her children when they attempt a new task. She seems to be doing what any mother would do.

Sue McGaw, a psychologist who heads the service, says: 'We showed her how to get attention by establishing eye contact, making sure the child is in the right position and then saying her name.

'And we would demonstrate nappy changing, for example, and she would watch and then try it herself. It is hard for these mothers to retain information for long, so we break tasks down into very small steps and make a simple, visual, chart which they can follow. If they get stuck we accept that it is our problem, not theirs.'

Margaret's affection for her children is clear. Every time Lisa comes near, she touches her, or strokes her hair - what any other mother might do, but for an adult who has never received affection, showing it is hard. According to Sue, many learning disabled adults have been mistreated as children or brought up in institutions.

'They haven't learned to communicate through their bodies. Their only recollection of touch has been abusive and they block off contact and find it very hard to unblock when they have children. We use play therapy and sensory activities - rocking, listening to music, playing in water - to try to help them make up the deficit.'

Every summer the SPS organises a mothers' group so that these, often isolated, women have the chance of contact. Last year Margaret was so determined not to miss a week of her group that, although she went into labour during one meeting, she insisted on coming back with the baby the following week. This summer the SPS is arranging a series of group discussions - using role play and illustrated leaflets - on 'emergency responses'.

It will be none too soon for Margaret. As we talked she brought in a tray of tea. The tray was put carefully on a table, but then she gave Lisa her own steaming mug and failed to stop her from wandering towards her baby sister lying on the floor. The psychologist with me intervened but it was clear how easy it would be for these children to be hurt, not through lack of love, but lack of foresight.

As Sue explained: 'You can tell someone always to keep hot mugs of tea away from the baby. Then they will be given tea in a plastic beaker and simply won't transfer the information because the situation seems different.'

There are Margarets in every community. They are the ones who fail to turn up to antenatal appointments, not because they are feckless but because they can't read the time or don't have clocks, or haven't grasped the concept of appointment systems. They live on the edge of a system which rejects them for being 'thick'. In the past Margaret might have lived her life in an institution or had every child taken away at birth. Today adults with learning difficulties live in the community. They will often have survived a childhood of taunting and neglect and long for an adult life in which they will, at last, be like everyone else. For most that will include establishing relationships and having children.

For those with the support of services like SPS this dream of humdrum normality may be achievable. But too often it takes a crisis before any help is offered and then parents, who have difficulty learning at the best of times, are expected to 'shape up' with the threat of a 'place of safety order' hanging over them.

As the reputation of the Special Parenting Service grows, referrals are being made earlier. Midwives are encouraged to watch out for women who may need support - those who never keep appointments, seem unable to absorb information, or have difficulty remembering routine things such as their own middle name.

Inevitably, parents will fail and Sue McGaw is not sentimental about their rights. 'You have to safeguard the child, but they won't be taken away from the parents until I have tried everything to make the family work.'

The Special Parenting Service, 57 Pydar Street, Truro TR1 2SS.

(Photograph omitted)