The hall of Ralph Butterfield primary school, York, echoes to the undulation of 60 chanting children, their voices rising and falling in rhythmic patterns, a criss-cross of individual incantations.

One child starts to whisper slowly, like a prayer. Another follows and another. They are suddenly silent, only to begin again, this time more urgently with raised and resonant voices. They try to imagine the soaring Gothic of York Minster and their voices echoing around the vaulting.

These 10-year-olds are making sounds, not meaning. Their words, all different, create a solemn cacophony. But if you listen closely to each pupil, you can hear something like the lines composed by 10-year-old Charlotte Green, “wing flapper prey stalker Head twitcher meat snatcher”, or Chris Smith’s, “moon howler prey seeker fierce terrorisor”, intoned repeatedly. Charlotte is describing an eagle, Chris a wolf - their own “kennings”, a compound expression with metaphorical meaning found in Old English and Old Norse poetry.

Duncan Chapman, a professional composer and musician, is directing the children with the help of Mick Gowar, a professional writer and performer. Chapman helps them improvise their mode of delivery, bringing their suggestions to life in a pulsating composition, fit for a space like the Minster, where they perform the piece, A Creation Mystery, with Year 5 pupils from two other York schools, Scarcroft primary and Westfield junior.

The performance in June - a musical re-enactment of the story of the Creation - was the first major educational event of a year-long programme leading up to the staging of the York Millennium Mystery Plays. This famous cycle, which retells Bible stories from Creation to the Resurrection (and which has been re-enacted every four years by York’s citizens under a professional director since 1951) will be held for the first time in York Minster next July. The director, Gregory Doran, is associate director of the Royal Shakespeare Company.

To mark the Millennium, however, the plays have been given a fresh and contemporary resonance with the involvement of the city’s youngsters. Delma Tomlin, chief executive of the York Millennium Mystery Plays, says: “The education programme is designed to build up the theatrical skill base in the city so young people can take part and support the plays in the future.”

Since Easter, Chapman, Gowar and Allison Clarke, a theatre designer, have been going into primary schools, encouraging the children to express in words, art and music the creation of light, water, birds, animals and the planets. Pupils have made dozens of bamboo flutes, rain sticks, bird and fish masks, and models of the planets, the sun and the moon. They made a “Jesse tree” to take into the Minster, full of Creation rhymes and synonyms. They composed a “Light” piece by thinking of as many words as possible to evoke light (Ralph Butterfield pupils came up with 59), selecting some of the words and putting them to music which they composed and played themselves. They also used the kennings and related images to form a “trail of discovery” which led the Minster audience to its seats.

Cathryn Dew, a part-time lecturer in music at York University who is education co-ordinator for the York Millennium Mystery Plays, says the children realised they were capable of composing on a grand scale. “At the beginning they would never have thought it possible to perform their own pieces in the Minster. But they wrote everything they performed, and needed no specialist musical training. With guidance they were able to use their innate musicality.”

Chapman says his job was to devise structures and working methods that enabled the pupils’ ideas to blossom and for their spoken text, home-grown sounds and compositions to fill the space of the Minster. “Lots of kids will have sung songs in the Minster,” he says, “but this was a chance for them to have ownership of the material.”

Sarah Welsh, a Ralph Butterfield pupil, relished being able to make up pieces. “Normally we just play (other composers’) pieces,” she says. “It’s good to have this chance and to think how it might work out in the Minster, where it’s all echoey.”

Chapman, who works all over the United Kingdom on large-scale educational music projects, is careful never to dismiss any child’s suggestions. His expertise lies in giving even the most tentative ideas some practical form, allowing pupils to assess their own degree of success and come up with alternatives.

Richard Ludlow, headteacher at Ralph Butterfield, believes the exercise has also been good for staff development. “The children have been really motivated by this,” he says. “It has made me realise that we don’t always give pupils enough opportunity to make their own choices.”

Anne Tee, a Year 5 teacher at Scarcroft, believes her pupils have benefited enormously. “It is refreshing for them to work with adults who are not teachers but professionals in other fields, and to experience different styles of communication,” she says. “The project has helped bring fresh ideas and methods into school.”

The performance of A Creation Mystery was followed on July 4 by a performance of Moses and Pharoah, a project involving children from York’s special schools which concentrated on the play’s medieval setting. The children were introduced to a sensory experience of the Middle Ages, discovering the sounds, smells and textures of a medieval city, and created their own sound effects for the plague of Egypt with resources similar to those available to medieval craftsmen. Their play was performed as part of the York Early Music Festival’s “Carnival of Time”.

York’s secondary schools will take part in a Symphony of Glass, in which pupils will be encouraged to write their own contemporary plays based on the Mystery Cycle, depicted in the Minster’s east window, for a performance in the city’s Theatre Royal next Easter. A series of training bursaries is also being made available for pupils wishing to learn theatre skills, to help build up a body of young people who can take the mystery plays into the future.

The education programme is being sponsored by the Arts Council, food manufacturer Nestle and the City of York Council. Gill Cooper, manager of York education authority’s performing arts service, says the city wants to give children the opportunity to experience the best and highest quality in art.

“We are initiating projects which take children way beyond their expectations of what they are capable of achieving,” she says. “We are bringing in performing arts companies to work with them to show what high quality arts professionals can do.”