Countless grown-ups retain bitter memories of school shows: as an elite of precocious thespians hogged the limelight, others would be allowed a token dunt of the glockenspiel or a cameo as “third sheep”, if they got near the stage at all.

Hillhead Primary pupils, however, can expect to look back more fondly on their theatrical careers. The Glasgow school allows all 320 of them to perform in its end-of-year musicals. “I feel that if we’re going to put on a show, we should have everybody in it,” says depute head Sheena Cadoo. “We also do a Christmas play for P1-3, and everyone is in it. I don’t believe in a small production.”

It is a huge logistical effort. The first challenge is to choose a suitable production. Few companies write shows which can be adapted for such a large cast. There must be a strong theme which is attractive enough to P7s and comprehensible for P1s, with tunes everyone can hum.

Last year’s show, A Big Green Adventure, came from Edgy Productions, which specialises in musicals that can be easily adapted to include real people and places. Its environmental theme is being followed this year by Cinderella and Rockerfella, a modern take on a pantomime from Out of the Ark Music, set in a world of celebrity and costumed by the school in the style of Grease.

The show is introduced to pupils only four weeks before the performance, so that there is no time for the cast to become jaded (but enough for everyone to learn their part). For the same reason, there is only one full performance.

Hillhead’s first whole-school show was The Bumblesnouts Save the World in 1998, and the big lesson Mrs Cadoo learned was that everyone had to know exactly what was expected of them. All staff are involved and they swap classes so that best use is made of everyone’s talents; infant teachers often work with older pupils and vice versa. An hour a day of preparation for all is typical.

There is no room on the premises for the show, since the largest could only squeeze in half the pupils, so it takes place in nearby Wellington Church. But the first time the cast performs there, is at the dress rehearsal. There is a “tremendous buzz”, as this is also the first time pupils see costumes and set-pieces.

In terms of staging, Mrs Cadoo does not want to see pupils “stuck in a big lump in the middle of the stage”, so there is no split between stage and auditorium, no curtain or any other physical divide. The audience’s attention has to flit to performers all around the church, as they appear up on the balcony, along the aisles and in the pulpit, while singing emanates from all corners.

The children’s colourful costumes are dotted around the church. In last year’s production, P1-2s were bluebells. When the character of Natura, queen of the forest spirits, “woke up” the flowers, little blobs of blue unfurled in unison.

There are no pupil stagehands hiding behind the scenes, Mrs Cadoo adds, because everyone should be able to see and hear the action and no one should be hanging about backstage for hours.

While older pupils take the main parts, there is a big set piece for each age group. This year, the P1s perform as animals in Cinderella’s kitchen, the P5s are paparazzi harassing the titular Rockerfella and the P4s host Hillhead’s Got Talent with pint-sized Simon Cowells looking askance in the pulpit.

The shows appear to have a long-lasting benefit, with many former pupils going on to take music and drama at secondary school.

“We like to think that we are nurturing an interest and love of the arts,” says Mrs Cadoo.

www.edgyproductions.com; www.outoftheark.co.uk.