Here are some facts about Boveridge House. An independent residential special school in a stately home on Lord Cranbourne’s Dorset estate, its 25 pupils (68 in its heyday) are aged 10 to 19, all with moderate or severe learning difficulties. Annual fees for private pupils and children placed and funded by local education authorities are about #163;5,000.

In May and December 1997, scathing OFSTED and HMI inspections of Boveridge pointed out that there was no governing body, no planned curriculum, no schemes of work, no assessment policy and no staff appraisal. The school was put into special measures. Parents submitted an action plan to OFSTED last month and have raised #163;100,000 to keep the school open. Miss Harper is to retire.

The inspection did not come out of the blue. For several years there had been what Miss Harper calls “khaki letters from the ministry”: demands from the Department for Education and Employment for the school to act on all the legal requirements placed on state schools in the past few years - and Boveridge counts as a state school because LEA-funded pupils go there. With Miss Harper in charge, it became increasingly clear, the DfEE would not get its key stages, its qualified care staff, its school development plan. But without Miss Harper, would there be a Boveridge?

Peggie Harper was sent to a London boarding school for orphans when she was four. At 14 she went to work, at 17 joined the Wrens, in her early 20s trained as a domestic science teacher and moved into special education.

She taught in some of the earliest integrated schools in southern England before setting up her own more than 30 years ago, initially in her mother’s front room and eventually - having seen the house advertised in Country Life magazine - at Boveridge, which is rented from Lord Cranbourne.

The setting is astonishing. Between the house and the wood and fields is a formal garden designed by Gertrude Jekyll. The children ride the school’s ponies each week, hens pick their way around the classrooms in the old stables, a pheasant stalks past Miss Harper’s bay window in the direction of the dovecote. The building exteriors look dilapidated, but inside are bright and comfortable vases of flowers, paintings and cushions. One child told his parents: “When I’m at Boveridge it’s like having dinner with the Queen.”

Gradually Boveridge’s reputation grew beyond Dorset. Pupils numbers rose. They all had different diagnoses - Down’s Syndrome, Fragile X, Prader-Will i, general delayed development - but similar problems. All of them were anxious, vulnerable, lacking in self-confidence. None had settled happily in other schools.

The happiness of the pupils is beyond question. HMI waxed lyrical about their mutual supportiveness, good behaviour and charm. They shake hands at every opportunity. They praise each other and protect each other from criticism or embarrassment. They switch off lights and close doors unreminded, caring for the house as if it was their home. Neither Miss Harper nor parents I spoke to knew of any child who was unhappy, nor of any parents who felt their children were not well-educated and well cared for.

Yet these children are not paragons. One boy who sits meticulously embroidering a picture as a present for his mother was expelled from three schools before he came to Boveridge. Another used to bite himself and others.

At Boveridge Miss Harper is their sergeant-major, marshalling and defending her raw platoon from the cross-fire of an intolerant world. She is there six days a week, 24 hours a day: “These children are like a family. They take turns helping me get the breakfast, and I wouldn’t expect a child to go to bed without finding me to say goodnight. They would be bullied in an ordinary school. They wouldn’t cope with the bell going; their small misdemeanours would be blown out of all proportion. Here they know they have someone to run to.”

There has been education at Boveridge. Parents attest to substantial improvements in their children’s reading and writing, as do educational psychologists’ reports on those who are statemented. The teachers - three full-time and two part-time - seem shell-shocked by the OFSTED on-slaught: they did plan, they did assess progress, they argue, but separately and in different ways. With support from a deputy head of special needs at another schools, whose advice was sought by parents, they are now conforming to common procedures.

And it is Miss Harper’s turn to be scathing: “I’m old hat. I find it extraordinary with all this national curriculum and planning that you can have a staff meeting and never mention a child. ”

Old Boveridge pupils come back year after year to open days. They work as messengers and postmen and on farms and in small family businesses. They send wedding photos, in troubled times some even telephone Miss Harper for consolation. In her own troubled times they have stood by her too: a former parent, hearing that by retiring, Miss Harper will also lose her home, has bought a house with adjacent cottages to be her home and income for as long as she lives.

The children cannot believe she is going. The parents know what they will lose, but also fear the devastating effect of the school closing - their children would be split up and sent back into a world which has failed them. Advertisemen ts for a new head were due to go out last month. Some staff are retiring; others, with varying degrees of enthusiasm, are staying on.

As Miss Harper ponders the prospect, the caged parrot beside her desk gives an angry squawk. “We have to accept the new things, we have to keep it going for the children’s sake. But I think its a pity you can’t be odd if it works.”