The boarding-school tradition in Ireland was for many years the preserve of the religious orders. Many families, especially wealthy farmers, chose boarding schools as fitting environments for young men and women to grow academically and spiritually in a controlled and disciplined regime.

Such establishments are thin on the ground today. There are only five schools that are exclusively boarding left in the country, and one of those, Our Lady's in Rathnew, Co Wicklow, has announced that it is to close its doors in 2005.

Of the 45 Irish day schools that are listed by the Department of Education and Science as providing boarding services, five will have withdrawn those services by the end of this academic year. The Irish boarding school is an endangered species.

The demand for boarding schools has dropped somewhat, as parents find agreeable day schools locally. But lack of demand is not the issue.

By far the biggest threat to the sector is the decline in the religious orders. Without live-in nuns and priests prepared to act in loco parentis, boarding schools must put up the cash to pay for lay staff qualified to take on one of the most responsible roles in education. It's not cheap. Even where schools can afford it, there are not many qualified people willing to take on the responsibility of other people's children round the clock.

"We made the decision to close the school because we simply could not get the appropriate staff," the principal of Our Lady's Rathnew, Rosemary O'Looney, explains. The Wicklow school for girls will close its doors next June.

The cost of going to boarding school in Ireland has been relatively low until now; Irish students can expect to pay between €7,000 and €10,000 per annum. It sounds like a lot until you take the cost of a private day school and add all the extras - sports coaching, music lessons, grinds, food, lodgings etc. In Britain and US, boarding school fees start at around €10,000 and from there the sky's the limit.

In Britain, the numbers going to boarding school are actually rising, largely due to a concerted effort on the part of British schools to recruit students from overseas. The sector has an umbrella body, whose sole purpose it is to attract students to the country's boarding schools.

Lucia Reynolds of the International Education Board of Ireland, set up to profile Ireland as an international centre for learning, has noticed a dramatic increase in requests for Irish boarding schools from foreign students. This increase comes just as the Irish boarding school sector is going into decline.

Can the Irish boarding school sector survive without the religious orders? One school in Kerry has found a way around the problem. The all-girl all-boarder Gaelscoil Coláiste Íde was in serious trouble in 1999, and the Mercy Order that ran the school was set to wind up operations. Reluctant to let the only all-boarder Gaelscoil in the State close its doors, parents stepped in and took over forming a limited company chaired by the broadcaster Micheál Ó Muircheartaigh. Five years later the school is thriving, and the board of management is planning to increase the current 100-strong student body. Coláiste Íde is the only State-funded boarding school here. Parents pay for room and board but not for tuition, bringing the cost in at a reasonable €4,220 per annum.

At the top end of the market, Rathdown girls' boarding school charges €13,000 per annum and the demand for places continues to rise. The school has 1,113 boarders, 15 per cent of whom come from overseas. Despite its success, Rathdown is just as demanding for staff as any other boarding school, and principal Barbara Ennis cites recruitment as a major problem. "We are constantly placing ads and running interviews and have still not come up with a solution," she says.

Part of the reason for the staffing squeeze in the boarding sector is the small class size. Of the dozen boarding schools surveyed for this article, the average class size was 17. The results achieved by many boarding schools are higher than average academic results, and many schools are not ashamed of publicising that. Blackrock College, Co Dublin, Cistercian College, Roscrea, Co Tipperary, and St Columba's College, Co Dublin, have all chosen to make their exam results known.

So, as demand for boarding increases both at home and abroad, supply is going down. The result is a likely price hike in the sector that many parents will be happy to absorb for the peace of mind that a boarding school can offer.

"Parents choose boarding schools for a number of key reasons," says Fr Peter Garvey of the Cistercian College Roscrea. "It is accepted that the academic standards will be high. Beyond that, students will benefit from a rounded education, strict discipline and a safe environment. They have a structured day, they don't have time to watch TV or play computer games or get into trouble because we keep them very busy."