Group.

Earlier this year, the nuns of the Abbaye Notre Dame de l'Annonciation, near Avignon, took a call. It was, improbably, Decca Records asking to visit. The company was launching a global search to find the world's finest female exponents of Gregorian chant - a talent contest for nuns. It had advertised in Catholic newspapers, hired a specialist nun-hunter, followed the leads. Two A&R men turned up at the abbey. The purity of the sisters' singing was obvious at once, yet the search continued: 70 auditions, from America to Africa. And then, in July, although warned that it would not find a more traditional order than the Abbaye sisters, Decca chose this group of 28 women, whose mystique and dignity are enhanced by their refusal to engage with the hype surrounding a record launch. They are wary of the world but say, 'We did this for others, for their spiritual wellbeing; it will bring peace to the people who listen to our music.'

While recording the album in August, the nuns decided they would do one interview to publicise Voices - Chant from Avignon. Then all went quiet. Had they changed their minds? Decca had to dust off its fax machine - the nuns' preferred method of communication. Eventually the fax warbles. 'We are sure St Joseph will help you to spread the disc,' the message reads, serenely rebuffing a marketing ploy to present the record to the Pope on his UK visit. But then, good news! They will welcome YOU magazine 'with joy', for their single interview. And so we set off - Caroline from Decca, Clara the interpreter and me - on a lengthy journey that starts in the small hours at St Pancras's Eurostar platform and ends in a cab ride through the fertile Provencal hills where the ochre abbey sits peacefully.

The interview is one of the strangest I have ever conducted: as members of a closed Benedictine order the nuns remain behind a grille, even in the parlour where they meet visitors. I don't discover the birth names of the four sisters in their black habits who come to talk. I know them as Mere Abbesse, Mere Prieure, the abbess's right-hand woman, who comes from Poland, Mere Scholastique, who is in charge of music, and the more junior Sister Anne. The first surprise is how young this community is: just two nuns are in their 80s, the rest in their 20s through to their 50s. And they seem younger because they are shy, dipping their heads in embarrassment at certain questions; they giggle and they look young too. 'It's monastic life,' they say, explaining they are not allowed moisturiser. 'It's the wimple - hides the white hair,' Mere Scholastique says, with the air of someone sharing a fashion tip.

How did they come to be here? 'At 18, I was going to do my baccalaureate but a friend brought me here to visit and it was a coup de foudre!' Sister Anne, 28, volunteers. She was religious from childhood though her family was not. She thinks that being a keen Girl Scout channelled her towards holy orders: a foundation course in altruism and hierarchy. 'None of us is 100 per cent sure of our vocation,' Mere Scholastique adds, 'but in the end you have to try.'