The Hogwarts juggernaut has brought with it a surge of interest in boarding schools. But the move to a surrogate home can be traumatic, for parents as well as children.

As the mother of two boarders, I know only too well the potential difficulties families face. My children are happy at their school, the large, socially mixed, charitable foundation of Royal Hospital school, Holbrook, Suffolk. But, however good the school, there is no escaping the fact that boarding is counter-intuitive; that parents of even the keenest children (mine are very keen) detest the partings; and that they are our children before they are school members.The only excuse for boarding is if the school is excellent:half a loaf is not better than no bread. If it isn’t a pastorally excellent, happy and caring school it shouldn’t take boarders.

We need to adapt; holidays become different (never book a half-term trip for a new boarder - the child wants to be at home). Boarding complicates life for working parents - you have to step down the working hours and pressure during the holidays to spend maximum time catching up with your child, because in term time you have no evenings.

Above all, you enter a triangular relationship - with child and staff - which must be made to work.

A good boarding school is a unique hybrid: somewhere between an educational community, a small independent nation and a large extended family. At their best - if the child is genuinely ready and suitable, and nobody should kid themselves that all children are - boarding schools do very well indeed by their pupils, offering stimulation and security, friendship and independence, and an efficient use of time. But they have to do it without damaging the children’s sense that they belong to their own family.

Sending a child to school because he or she is “difficult” is dangerous and stupid. Happy children from happy homes make happy boarders. Pushing a problem 50 miles away doesn’t solve it.

I made these points in a speech to a recent Boarding Schools Association conference on “parenting the boarder”. Heads told me afterwards that they wished their staff could have heard what I said. Many boarding staff have never been boarding parents, they said; many would like a guide to offer new parents. So the association commissioned me to write a booklet.

At the core of Parenting the Boarder is the message that adults on both sides must listen, not only to the pupil but also to one another. Staff must understand how forlorn new boarding parents feel. The child before you may be a keen sportsman, joker, junior football captain - but to his mother he is a tiny, distant, endangered cub in a strange jungle. That 10pm phone call to the housemaster about socks may seem unduly hysterical, but listen hard, because it isn’t really about socks at all.

Administrative details, such as having to register an 11-year-old child with the school doctor, and classify her as a “temporary resident” while she’s home, can drive a mother to tears and the gin bottle. It is vital that boarding staff don’t scoff or belittle the feelings of bereft new parents.

Staff should also be aware that parents know a lot about their children. When any complex new item enters your life, it pays to read the manufacturer’s manual. A child who is cheerful at school may be expressing the negative side of boarding life on the phone to his or her parents. Mum and dad get the tough stuff, because it’s safe to blow off steam to them. Do not be insulted if an extraordinary picture of your school is fed back to you by a distraught parent: it too is valid. Listen and learn.

If I had to spell out parents’ pleas to boarding staff, that would be the first one.Others would be:

* Don’t grass. If a worried mother rings about a child’s state of mind, don’t curry favour with the child by saying: “Your mother’s worrying about you. Mothers, eh!” Try to spot for yourself what the problem is. And never ignore moping, solitariness or languor. Not all unhappiness manifests itself in misbehaviour. The “good” child may need help too, and it is parents who will alert you to such subtleties.

* Communicate clearly. Email is a godsend for answering parental worries, but if you have to leave a message on the answerphone, make it explicit. A call saying “ring school immediately” causes cardiac crisis in the separated parent. If it’s about a vaccination permission or some such trifle, say so.

* Make parents realise that they have to be available. If they go abroad, you must know; if the mobile will be off for a long time, you must know. Parents represent the still centre of a boarder’s turbulent world: one at least has to be stable, and contactable.

* Tell parents that you know relating to them is part of a boarding teacher’s job. A good relationship makes the school’s job far easier, because it gives an understanding of what each child is like and where he or she is coming from. You are trained to be aware of broken homes, but should also be aware of the stresses that affect close and happy families: grandparents or pets may die, or there may be a risk of some family crisis finding its way into the local press, or even national, media. The child is your business, so the family is your business.

* Be prepared to have meetings, and not just over doomy stuff like expulsion. In the last resort, whether it is discipline, work or just happiness that is elusive, child, parent and staff need to sit round a table and thrash it out.

A house head or tutor is not a mere commercial contact: he or she is a new but detached part of the family. When your child enters a boarding school you add a few dozen people to your tribe. This can be rather wonderful: a new kind of link to the outer world, a new layer of aunts and uncles for the teenager to relate to.

Teenagers, after all, need a lot of people, because they are prone to fall out with some of them from time to time. It takes a village, as Hillary Clinton would say.

Yes, it all sounds like hell. Staff may curse. But the booklet does, you will be relieved to hear, also set out the duties of the parent towards the staff and school. And those are another story.

‘Parenting the Boarder’ is available at pound;5 from the Boarding School Association, Grosvenor Gardens House, 35-37 Grosvenor Gardens, London SW1W OBS, or can be ordered at www.boarding.org.uk