Channel crossings: The Kent prep school that's attracting French boarders

It may look like a very British country boarding school, housed in a George Devey-designed Victorian mansion. But Northbourne Park in Kent is, according to headmaster Edward Balfour, a "mid-Manche school". Each year, it plucks three-dozen pupils from French schools in Paris, Marseille and Madrid, and sees them through the Sixième and Cinquième – Years 7 and 8 – alongside English pupils.

It's not just a way of boosting numbers at a school of fewer than 200 pupils, French included. Nor is it a scheme to give affluent children from the Continent a taste of English country boarding school life. Apparently the programme actually helps the English pupils to learn French.

"The standard of the French among the English pupils here is incredibly high, and part of the reason is that they're exposed to the accent at all times," says Balfour. "They realise that language is not something you read from a textbook; it's not something that's just taught in lessons. It's a way of life and it's a culture."

The French pupils are taught separately from English pupils and the two groups each follow their own curriculum. The French study the Cned, and take exams set by the Lycée Français in London. This allows them to slot straight back in to the lycée system once they leave Northbourne.

All the children board together in mixed-nationality dormitories, dine together in a relaxed, Gallic manner and play sport – even cricket – together. Each English child in Years 7 and 8 has a "correspondent" in the French stream. They can go to each other's homes at weekends and holidays, and have a "business lunch" every Friday, to talk about how things are going.

Thanks to its location, not far from the towns of Deal and Sandwich, Northbourne is able to offer a minibus service from Ashford International, the Eurostar station about 40 minutes away. In fact, all French and Spanish pupils' travel arrangements are taken care of, which is why their parents pay a £650 premium on top of the standard term boarding fees of £6,016.

The school has been operating a language programme from its sprawling 100-acre home on Lord and Lady Northbourne's Betteshanger Estate since 1990. It has never done any specific promotion, and across the Channel the scheme runs by word-of-mouth on the Parisian dinner-party circuit.

Looking at the former home of the Northbourne family, it's not hard to see the attraction for French parents. "For them, this is the ultimate British experience," says Claire Olcott, who is French and has three children at the school. "It's so British and they love the outdoor education, the woods – generally the whole setting. You do not get that in France, even at good private schools. Besides, a lot of these children are from inner Paris, so the contrast is immense."

The benefits for the French pupils are clear. But one of the main criticisms of the programme is that it is just a glamourised exchange scheme – a way for posh French children to learn English – and that the English children get nothing out of it.

The school says that all children at the school, whatever their nationality, benefit from the programme, because they learn about other cultures, life in different countries and make lasting friendships.

Listening is, of course, vital to language tuition. Just by hearing the language, children's performances can be improved. "If you really want to interact with people in another language, you need to attune your ear, and it's often difficult for schools to provide that amount of listening time in the classroom," says Teresa Tinsley of Cilt, the national centre for languages.

And yet, after nearly 20 years of operation, the Northbourne model has not caught on. David Hanson, chief executive of Independent Association of Prep Schools, says he would be keen for other schools to look into the idea, which works well in principle, but is difficult to turn in to reality.

Speaking to other prep schools in Kent, all of whom share Northbourne's proximity to the Channel Tunnel, it's clear the idea is unlikely to catch on any time soon. Ashford School says that while it does have boarders coming for short stays, this is done on an individual basis, not in groups, and it is purely to improve the French pupils' English. Sutton Valence, the school near Maidstone, says it "wouldn't have space for that sort of thing". St Edmund's, in Canterbury, says it is completely full up.

So what makes Northbourne so special? Size is important. The larger Lycée Français in London tried a similar programme, but found that there was no interaction between the different nationalities. At Northbourne, the intimacy allows pupils to mix – and be mixed – readily. The huge rambling country house also gives the school more than enough space. Assemblies can even be held in the family living room.

French is important to the history and culture of the school. Lady Northbourne, who pioneered the project as chair of governors, is French and the school now has a number of bilingual and French teachers. The French curriculum is exclusively taught by native speakers. Most important, Northbourne has its charismatic French deputy head, Patrick Papougnot.

The school at one point experimented with teaching both English and French pupils history. But it was unviable. The process of getting the French system accredited – "homologised" – by the French ministry of education is a bureaucratic minefield, which few seem to have the ability to understand, or the willpower to see through.

"It took us 15 years, with ups and downs, to really put things together," says Papougnot. "Perhaps it's the size of the school here, or the atmosphere in which we work – quite relaxed but still very much focused on the academic process. But we all know each other very well and we have respect for the way we are. Even the parents are quite Francophile now."