Peter Harrison, teacher, composer and musician, has an abiding memory of the little girl who came up to his Land Rover to beg while he was touring Ecuador with the British Council. The party of musicians, including Harrison, a professional flute player, were appalled by the deprivation suffered by the children they saw living on the streets. And on this occasion Harrison watched with horror as the blonde toddler - very like his own two-year-old daughter - approached their vehicle with open hands.

On his return to England he decided that all royalties from his musical script This is the Christmas Story, which he had written for primary schools with a grant from the Arts Council, should go to a charity for street children.

This Christmas, more than 20,000 primary pupils from Cornwall to Shetland will be performing Harrison’s choral narrative. As well as paying royalties, many schools will be holding collections for Children of the Andes, a UK charity which funds childcare workers to support, feed and educate street children in Colombia.

Teachers are finding that Harrison’s mix of catchy songs (which can be adapted for all levels of singing and instrumental ability), and his simple but challenging narrative, help to bring the Nativity story to life. The fact that performances raise money for charity only helps to reinforce the Christmas message, they say.

Harrison’s previous compositions, Longships (the story of the Vikings and their times) and Hadrian’s Wall (about the Roman invasion and life in Roman Britain), have also been performed by hundreds of schools. Harrison, who left full-time teaching in the late Seventies to pursue a career in performing and composing, holds workshops for teachers and pupils. He estimates that over the past 20 years he has visited 1,000 schools, and has seen “an incredibly varied level of musical provision”.

When he writes musical scores, he bears in mind that in some schools there is very little singing and instrumental work, while in others music is at the centre of the curriculum. This is the Christmas Story, aimed at key stage 2, comes with backing tapes for schools where staff have minimal musical skills, but there are additional harmonies and instrumental parts for schools that can handle a more challenging score.

Nigel Hayward, head of music at Sandwick junior high on Shetland, says Christmas Story has enough repetition for children to memorise songs easily, but it also has a beautiful narrative, mixing everyday language with text from the King James Bible. “Christmas music is a massive industry in itself and there’s a lot of rubbish about, but this is good quality and it suits the singers,” Hayward says.

Pace, variety, an easy range for children’s voices and an opportunity for improvisation have been skilfully provided. “I intend my work to be user-friendly,” says Harrison, “but also challenging.”

At Badger Hill county primary in York, Ian Reavill, class teacher for Years 4 and 5 (and a writer of pantomimes in his spare time), has added some Yorkshire slang to the script. While Badger Hill shepherds talk of going to Bethlehem “to see this thing which is come to pass”, they also complain of feeling “a bit parky” in the open fields.

Alexander Morrison, aged nine, is full of enthusiasm, especially for the music. “It makes the Christmas story seem really exciting,” he says. “I find myself humming the songs all the time. They make you feel really jolly and free.”

And as Emily Nicholls, aged 10, says: “It makes a change from ‘Rudolph the Red-Nosed Reindeer’.”

‘This is the Christmas Story’ ispublished by Sound Music, 25Turners Croft, Heslington, York Y010 5EL. Tel: 01904 410298