The idea was inspired by the short stories of George Mackay Brown, and a piece of music based on them by composer Alasdair Nicolson, but the end results are very much the work of the children, says project manager Naheed Cruickshank.

Work began prior to the summer break with visits to Primary 7 classes at the five schools - Househillmuir, Darnley, St Angela’s, St Vincent’s and St Bernard’s - by Nicolson and three players from the SCO.

Those sessions introduced the “spirits” who watch over the house in Mackay Brown’s collection, and some of the related musical ideas which Nicolson worked into his own composition.

Since then, the project team - Stephen Deazley, Gerry Ramage, and five players plus the education staff from the SCO - has been working with all the schools, helping them to develop their own particular versions of the theme. Each school chose part of the house, and devised its own ideas on the nature of its presiding spirit, expressed in words, music and movement.

At Househillmuir last week, those ideas were well advanced, and the final work was shaping up. But even then, new ideas were still emerging from the children.

“It has been hard work, but they have taken a lot from it in terms of language awareness, self-expression, and making use of their imagination,” said their class teacher, Liz MacLaren.

“The performance has given them something to aim at. We do quite a lot of music and drama projects in school, but there is a huge difference in having the input of professionals like Stephen and Gerry.”

The choice of locations reflects a fascination with the darker corners of the imaginary house, but Househillmuir chose the most unusual - under the floorboards.

There, the queen (SCO bassoonist Alison Green) sends out her soldiers to check on the house, and report back. The songs pupils have devised reflect their purposes, soft and slithery as the spies set out on their mission (“creeping quiet, keeping quiet”), staccato and urgent as they return.

Their contribution will slot into a programme in which all five projects will be integrated in a single linking structure, directed by Gerry Ramage.Both he and Deazley see their role as allowing the children to form and express their own ideas within the structural requirements of the theme.

The project also has a visual dimension. Artist Patsy Forde conducted in-service training sessions with the class teachers from all five schools,but - unusually in her experience - was not involved in working directly with the children. They formed their ideas with the teachers and produced drawings, painted stage backgrounds and head-dresses, some of which will be used in the performance.

The performance will take place before an invited audience of parents, relatives and other pupils at Bellarmine Secondary School. While members of the project team acknowledge the importance of the final production they stress that the process itself is even more fundamental. The children have been exposed to ideas and forms, both musical and theatrical, which are not part of their everyday experience.