The first thing you notice on entering the International School of Aberdeen - formerly the American School - is the display on the main wall of the reception area commemorating events on September 11.

In particular you notice the newspaper headline “Islam offers no refuge for the terrorists”. It is the only newspaper cutting in the display. Above it is an array of “Messages of Support from Friends Around the World”, a neat row of letters and e-mail messages. A senior pupil’s montage, “Terrorist Attack in America”, takes centre place. On the table below the display, among the cut flowers, is a donation box for the victims and their families and a book of condolence.

In the broad arc of the entrance window stand the flags of many of the nations of the world. At the top of the stairs is a welcoming figure: a life-size couthy cut-out of a mannie in a kilt and tammie.

Apart from the security man at the entrance lodge, the atmosphere is astonishingly relaxed - as relaxed as it normally is. Senior students pass to and fro en route to morning classes. They chat and laugh but they do so politely. There is a sense of self-direction and self-motivation about them.

The accents are mainly North American, though European, Middle Eastern and Asian students also are apparent.

A student sporting a perfectly manicured Mohican haircut of mountainous proportions goes by.

“It’s not just an American thing. Uniforms are not part of the norm in European schools,” says the school’s director, Doug Osbo. “But the students have to look presentable and anything culturally demeaning is barred.

“A lot of visitors are struck by a sense of relaxation on entering the building but there are structured expectations,” he says.

No one could doubt that, given that more than 90 per cent of ISA graduates go straight on to university. The other 10 per cent tend to be those who are taking a year out or have been called up by their country to do national service before going on to higher education.

There are 26 nationalities represented among the 400 pupils at the school. They range from nursery children to grade 12, the equivalent of Scottish sixth year. The staff also is international, including Scottish, English, Irish, American, Swedish, French, Spanish, Portuguese and South African teachers.

In the aftermath of the New York, Washington and Pittsburg terrorist attacks there have been no tensions or disagreements among the various nationalities and cultures, including Muslim pupils, represented in the school population, says Mr Osbo.

“In any one class we would have American, European, Asian and Middle Eastern pupils sitting next to each other wondering why this was happening when we all get along together here.

“None of our immediate families were affected.

“Naturally our pupils wanted to discuss it but there was not one reported incident of anyone feeling they were being singled out.”

The international ethos is central to the school.

It was founded in 1972 to cater mainly for the children of Americans working in the oil industry. It moved to the nine and a half acre estate of Fairgirth, near Cults, in 1996 and changed its name to the International School of Aberdeen.

“There were a lot of American schools in Europe and Britain after the Second World War, often where there were large US firms and embassies operating,” says Mr Osbo. “In later years they moved towards becoming international schools as multinational companies developed with a multinational workforce. These schools operate all over the world to provide a seamless education from school to school as parents move around the globe as part of the multinational workforce.”

He cites the example of a Chinese student moving from Damascus to Aberdeen and slotting into the same curriculum and ethos. Sometimes pupils’ parents have to move country at a week’s, or even a day’s, notice.

With senior school fees at the ISA around pound;10,000 a year, these pupils are the privileged few.

“As in any independent school, the pupils have special opportunities but our responsibility professionally and ethically is to make sure that these opportunities are channelled and not wasted,” says Mr Osbo.

Getting the pupils into higher education around the world is the academic aim ISA sets itself. The International Baccalaureate which it operates through the two senior years is based on what the school’s welcoming booklet calls “the two great traditions of learning - the humanities and the sciences”. Developed in Geneva in the 1960s, and now used across the globe, the baccalaureate is a rigorous and demanding system of intellectual excellence and widely recognised for university entrance, including Harvard and Oxbridge. It covers not only a standard academic curriculum but also an extended research essay of 4,000 words on a subject of the pupil’s choosing, a course on the theory of knowledge to promote critical thinking and a 150-hour extra-curricular creativity-action-service programme, which includes community service.

“To breed the idea of service to the community is integral to the school ethos,” says Mr Osbo, echoing the ISA booklet, which talks of each pupil becoming “an ethical, responsible, productive and disciplined citizen of the world”.

In a real sense the pupils at ISA are citizens of the world and, if ISA is an exemplar, such schools breed a genuine sense of internationalism. The pupils form an itinerant multicultural community, often criss-crossing with each other in schools around the world and sometimes meeting up again at universities.

At university, graduates from international schools tend to be attracted to cultures and societies other than their own, says Mr Osbo, and tend to make international friends rather than being drawn soley to people from their own (or their parents’) ethnic or cultural backgrounds.

“This is because of the international experience they grow up with. We set out to promote a cultural understanding and we are not dogmatic in any nationalist or monocultural sense,” says the director.

“We are guided by over-arching moral principles and, by virtue of our being international, we are not put under any monocultural expectations.”

Knowledge of other cultures is the benefit “international children” appreciate most when they are older.

There is no formal religious education at ISA but all aspects of religious festivals which are significant to pupils are incorporated into the daily curriculum, as are the various national days of the different countries represented.

“This is not formalised but it permeates the entire culture of the school,” says Mr Osbo. “It would be virtually impossible to put any one religion over any other.

“With regards to events like September 11, we understand and accept our moral obligation to explore any issues arising while also defining the commonalities of different religions.”

In the broad curriculum, there are two main points of reference: the host country and the pupils’ own countries or cultures.

“The literature taught could be North or South American, European or non-Western, and this pattern applies in social subjects such as history or geography,” says Mr Osbo. “But we always involve the host country’s culture because that’s where we are. You keep bringing it back to those two points of reference: where you are and where the individual kids come from.”

All teaching at the school is English language based and it provides support at all levels for those who have English as a second language. While English speakers might sit French, Spanish or German as part of the foreign language component of the baccalaureate curriculum, their European peers will sit their own native speakers’ papers.

The internationalism also pervades the sports programmes. ISA teams take part in basketball and volleyball competitions both locally and with other international schools in tournaments as far spread as London, Madrid, Cairo, Rabat and Stavanger.

In local basketball and volleyball leagues, ISA is a “powerhouse”, says the proud director. But in football: “Well, we provide good competition in the local leagues,” he admits. “That is, we generally get beaten.”

Although a day school, teachers are expected to take extra-curricular activities at nights or weekends. Apart from sport, these vary from calligraphy, tapestry and book binding to Scottish country dancing, theatre and story writing.

Class sizes at the school are small, rarely above 20, which helps to account for the academic success rate of the school. It also operates twilight support classes wherever there is a demand.

Another aspect of the school which is unusual from a non-international teacher’s point of view is the transient nature of the population. Mr Osbo has spent 22 years in international schools around Europe and reckons the average stay in any school for a pupil is three years maximum.

“International schools do not, by definition, have a steady state population. Every year on average a third of your students will be new. That means freshness and dynamism and, although one pupil may have just lost his or her best friend, it also means they’re looking out for another best friend. That militates against cliques.

“Pupils do have to be able to settle quickly but that’s what schools like ISA are designed for.”

Walking around the school, visiting classes from nursery to senior school, the friendly family atmosphere which is generated by the pupils and staff is striking. Every other classroom has at least one comfortable sofa for students to sit on. You can see and feel how people are made to feel at home and settle in easily.

But dark shadows have been cast since events on September 11. International schools have a broad support network and e-mail systems and shared websites have been busy recently with requests from schools in areas which might be affected severely by disruption in the developing campaign against terrorism, asking for materials on counselling children and on evacuating schools.

“There have been no evacuations as we speak,” says Mr Osbo. “But in the present circumstances international schools in certain areas will be having to make contingency plans.”