Musician Nigel Osborne gazes up to the horizon, where half a dozen children are embracing a 20-foot-high stone. “Are we ready, Ireland?” he bellows.

Ireland is indeed ready. Led by a young boy in a red baseball cap, the group peel away from the stone; and with arms in the flying position zigzag in a line along the amphitheatre’s rows of seats, until they reach the circular space at the bottom, where they get ready to go into their music.

This is not some ghastly junior version of the Eurovision Song Contest, but a full-scale rehearsal of work devised by 70 pupils from three schools in Somerset. The following day they’ll be giving a performance that forms part of an unusual integrated arts project, the European Community of Stones.

The rehearsal is taking place in the amphitheatre built into the hillside at Frome Community College. All round the top edge stand 12 vast and contrasting slabs of stone, each brought here in 1992 from one of the then 12 member countries of the EU.

Over these three days the children, aged seven to 16 and drawn from St John’s First School, Selwood Middle School and Frome College itself, have been using the rocks as a stimulus to their imaginations, exploring shape, colour, texture, and pattern to create music, movement, costumes, and sculptures to be used as props in the performance.

The stones, of all shapes, sizes and colours, are intended to symbolise European links and integration, but also diversity.

The project is the brainchild of artist Barry Cooper who sees it in terms of the song lines of the Australian Aboriginals.

“The quarries in Europe where the stones have come from are their conception sites, and their songlines are their journeys to Frome,” he explains. “If you think of the stones as one end of an instrument, with strings all across Europe, we’re trying to vibrate those strings.”

In order to get the vibrations right, he’s working for three intensive days with composer Nigel Osborne, professor of music at Edinburgh University, and with performance artist Annabelle Macfadyen, who’s co-ordinating the movement elements.

Together Osborne and Macfadyen have been encouraging the children to create sounds and rhythms, shapes and movements that reflect their feelings about their piece of granite, marble or limestone. “We’ve tried to get them to think of the personality of the stone,” Macfadyen says.

Over in the art room and on the grass outside, under the eye of Barry Cooper and their teachers, other groups are putting the finishing touches to a plethora of vibrant costumes and complex sculptural images, unabashed by the presence of a film crew capturing their work for a forthcoming Channel 4 programme.

The choice of design and images - made by the children rather than the adults - is striking: volcanic lava for Belgium, a cage for land-locked Luxembourg, the warrior spirit for Greece, protectiveness for Holland.

For most of the children, and certainly the younger ones, putting together a large-scale performance of this kind in a short time has been a novel experience, and one that has presented them with a good many challenges, both artistic and social.

Frome’s head of art Tamsin Thomas says: “It’s been quite a change for my GCSE art students. They’re used to doing year-long projects, so it’s been good for them to find out what’s demanded of them in something more intensive. Instead of the usual planning there’s been a lot of making do.”

Teachers from all three schools also see social spinoffs from the decision to have mixed-age groups. “It’s helped my children’s communication skills, ” says Emma Cypher, from Selwood Middle. “They’ve had to learn to compromise, to give and take with the first-school kids.”

At the end of the rehearsal, Nigel Osborne reflects on the value of such an integrated arts project. “Music is related to other art-forms, and had been since civilisation began,” he observes. “Children deserve the chance to have this kind of experience.”

The project will be featured in Channel 4‘s School at Work series on October 18 at 11.35am.