It has not simply been a case of carpeting the dorms. Schools that once saw it as their prerogative to take the child and shut the door to parents until the next holiday have had to adapt. Boarding is out of fashion and has had a bad press, the upper and middle classes stigmatising it as an oppressive rite of passage they can do without. Schools have had to listen to parental desires for closer contact with their children. Parents, 40 per cent of whom are now first-time buyers, want a gentler, more flexible, homelier and more protective environment, and they want ready access.
More than 30 boarding schools have closed since 1985 and many are not yet out of the woods. None can rely on the loyalty of old boys and girls. "Long gone are the days when you do something for your child just because you did it yourself," said Debra Price, the development director of Benenden School in Kent, which once nurtured the Princess Royal.
A growing number of parents tend to dip in and out of the boarding system as and when they can afford it and they expect value for money. Schools have invested millions in building programmes to improve sleeping accommodation, for instance, or reduce the size of dormitories, provide single rooms for sixth formers and improve academic facilities.
They have also attracted many clients from abroad, particularly the Far East, Russia and eastern Europe. One head said: "If we answered the demand from the Pacific rim we could double our numbers overnight." Most schools are careful, however, retain a balance between students from this country and abroad. Adrian Underwood, the headmaster of Moira House School, Eastbourne, East Sussex, and chairman of the Boarding Schools Association (BSA) has established "parental representatives" in Paris, Germany, the Far East and North America. He said students from overseas now made up 50 per cent of the school's intake, of which 14 per cent were foreign nationals.
Pupil supervision and care since the Children's Act has intensified in many schools, with counsellors, psychologists and dyslexia services. The BSA offers staff training on the management of boarding houses, legislation, bullying, relationships between staff and pupils, self-awareness and stress management and adolescent issues such as drugs, sex, alcohol and eating disorders.
Schools able to make economies of scale are most likely to thrive. The big public schools are unlikely to go under, though they too have been under pressure. Parents expect schools to offer the full academic fare and a wide range of extra-curricular activities. Gone are the days when pupils were left to kick their heels at weekends. As one head said: "Boarding must not mean bored."
Boarding schools deny that discounting goes on but most admit to helping parents in difficulty wherever possible. "It's a broad balancing act that schools have to undertake," said Mr Underwood. "You are dealing with individual young people and you have to see them through to a stage. It's not easy. I've seen seven boarding schools close in this area alone in recent years."
After an alarming decline in numbers in the late 1980s and early 1990s, however, some schools have seen their figures stabilise and even improve in certain age bands - there has been a growth in sixth-form boarding, for example, and many boys' schools in particular have become co-educational. Schools have had to market themselves rigorously - many now employ PR agencies, marketing managers and development directors - and they have had to change to meet needs, or define their specialisms more clearly.
Ampleforth College belongs to the largest Benedictine monastic community in Europe. It has remained single sex and is picking up numbers at key stages despite its rural site in North Yorkshire. This year more boys have joined Ampleforth Junior School at all ages and Ampleforth's sixth form is "virtually full". Father Leo Chamberlain, the headmaster of Ampleforth, believes this is because parents, not all of whom are Catholic, are attracted by the school's strong identity. He said: "This flows from our mission for the Catholic and Christian churches in this country. We are ministers of grace, not moulders of character. We offer what we believe and the boy is free to respond to the offer." Although the professional classes are facing unprecedented financial insecurity and may therefore board a son or daughter for only part of his or her education, Fr Chamberlain believes that schools with a clear sense of purpose give parents "something to stick with". Although Ampleforth has had to "constantly update", inherent in its structures was a deep sense of continuity with the monastery.
There are 14 schools, including Ampleforth, and 2,000 boarding pupils in the York area. These have recently joined forces to promote the city as a distinctive boarding centre and have even considered advertising at King's Cross Station in London. Ian Small, the headmaster of Bootham School in York, said: "York is only two hours from London by train. We have to make the most of that and what the city has to offer."
"Some people would call it niche marketing," said Alison Willcocks, the new head of Bedales, the progressive co-educational boarding school in Hampshire. "We stand for breadth, for caring for the whole person and for a family atmosphere. We survive as a boarding school because parents say 'We want Bedales first, and then we want boarding'."
Unlike many boarding schools Bedales has always been flexible about allowing pupils to go home at weekends but this trend has become more established in the school, largely to help professional working mothers.