British teachers often shake off the A-level syllabus along with the dust of their home country when they decide to work abroad. More and more are now teaching towards the International Baccalaureate diploma and they seem to like it.

Recognised by universities and increasingly considered by schools disillusioned with our own A-level and AS level hotch-potch, the IB diploma is gaining ground. Last month, 18,000 candidates worldwide sat the diploma exams, an increase of 3,000 on last year. It is offered by 968 schools in 107 countries. In the UK, 42 schools now offer the diploma.

To Lesley Murphy, who has been teaching IB English language at Marymount international school in Rome for two years, the baccalaureate programme is simply the best. She became an IB examiner in 1997 while teaching at the international school of Geneva.

“There is no more complete or academically demanding matriculation examination in the world,” she says. “Six subjects: three or four at higher level (this means 17 texts in English, for example); two or three at standard level; a research paper; a theory of knowledge dissertation; and hours of community service over two years. Students need to be academic lions to sustain the rigours of the programme. Most do.”

Jonathan Jones, who teaches English to the 930 pupils at St John’s international school in Brussels, also praises the IB for helping to turn out citizens of the world. He says: “The IB offers a wider range of possibilities by specifying author rather than title. There is also the world literature component, obliging students to study texts written originally in a language other than English.”

The Swiss-based International Baccalaureate Organisation (it has UK offices in Bath and Cardiff) runs programmes for primary (three to 11) and middle years (11 to 16), which are teacher-assessed, as well as the pre-university diploma.

The diploma was developed with funding partly from UNESCOand it is available in English, French and Spanish. The exams are assessed by external markers. Diploma students study six subjects in six areas: two languages, mathematics, experimental sciences, creative arts, and humanities. On top of that there is the interdisciplinary theory of knowledge course, which encourages questing and questioning, and CAS (creativity, action, service), which is involvement in community service and activities such as theatre production and sport.

The idea of the IB was to establish a common curriculum and university credential for geographically mobile students. At diploma level, the 4,000-word extended essay is designed to give them a taste of university-style research.

In fact, the IB diploma has outgrown its original ambition. Its keenness on the interrelationship of subjects and on questioning received wisdoms is rapidly turning it into the matriculation for Europe for the 21st century. It could be that A-levels will give way to the IB faster than sterling to the euro. It has great appeal to selective British independents who feel the A-level gold standard has tarnished.

The IB mission statement says that the programme aims for “intellectual rigour and high academic standards” and that it wants to produce “critical and compassionate thinkers, lifelong learners and informed participants in local and world affairs, conscious of the shared humanity that binds all people together”.

It is easy to be cynical, but Ms Murphy and others in her position have seen how it works. She says: “As I watch a pair of Saudi princesses play football with a group of Italian boys in the grounds of this Catholic convent, I have a growing conviction that the future, not of my country but of the world, is being created in my classroom.

“I have had the privilege of educating tomorrow’s leaders, some by birthright and some because they will be in the right place at the right time with the right qualifications and, above all, an openness of mind that will allow them to surmount barriers that a limited cultural persective can create.’ To find out more, see www.ibo.org