The Red Balloon is a short, award-winning film by Albert Lamorisse, made in 1956, starring his five-year-old son Pascal. Pascal is an only child living in Montmartre. His parents don’t understand him and he has no friends at school. One day he finds a red balloon tied to a lamppost. The balloon has special qualities but it is an independent spirit, and will not be controlled by Pascal or anybody else. It won’t tolerate adult “rules and regulations”, much to Pascal’s amusement. Because of the balloon’s special qualities, Pascal achieves a new status among his peers, and there are adults who would like to own its magic. He is not prepared to share his balloon, however, and as a result it is hounded and destroyed. All the balloons in Paris revolt, and come to Pascal’s rescue.

I empathasized immediately and profoundly with Pascal.

In 1984, at the age of 26, I was appointed artistic director of Contact Theatre Company in Manchester which produced theatre specifically for young audiences. It was difficult, however, to find work for the very young. I read many hideous, sanitised adaptations of fairy tales and popular children’s fiction, which seemed to me patronising. Some plays relied on what people call “audience participation”, where they are forced to respond in unison, usually to scream, only to be ordered to shut up. I was looking for a children’s theatre that was as ambitious as adult theatre; a theatre that could entertain, without bullying, and help its audience cope with new or unsettling experiences.

Having failed to find a suitable script I decided to have a go at writing one. I had written for adults before, and had had three plays produced professionally. I decided I would adapt a children’s story that had meant something to me - “a fairy tale without the fairies”. I applied for the rights to adapt The Red Balloon. I had an idea about how to do the balloon (I’d spent some years at school, playing guitar, backing a conjuring monk, who performed tricks with a magician’s cane that looked as though it was floating in the air, and a silver ball that rolled up and down the hem of a large handkerchief); the film had no dialogue so I could invent my own, and as many of the characters were nothing more than brilliantly observed vignettes, I could let my own experience inform their development. Also, I had had the good fortune to work with the theatre music composer Mark Vibrans on a couple of productions that year, and we were ready to collaborate on something more substantial.

Unfortunately, I had to wait four years before I got a response to my application for the rights. Mark and I shelved the project and I started work on an adaptation of Raymond Briggs’ The Snowman.

This story has many of the same qualities as The Red Balloon and I like to think I made a riveting piece of theatre out of it. The starting point was pictures. I became fascinated by the challenge of making the seemingly ordinary and mundane theatrical. I was intrigued by the way my own two young children seemed to have to relive what I considered to be very simple experiences over and over again to understand them, or they had the ability to find meaning and tension in minute detail. I enjoyed embuing simple activities with enormous dramatic tension.

The meeting of two characters on stage, if examined closely enough, could take three minutes as opposed to 30 seconds. This was perplexing to some adults, who grew impatient with the content while admiring the skill of the performers and direction, but it was very effective with the children, some of whom were as young as two. Like The Red Balloon, The Snowman is about loneliness; about being a child in an adult world; about making a very special friend, and it is about loss.These are themes that children relate to.

I am sure some children go to the theatre and suspend their disbelief, but others, because they are more in tune with the purpose of “play”, experience it more objectively and therefore its effect is greater. I don’t think the theatre, whether it is for children or adults is about putting reality on stage. In order to reveal the essence of a moment an artist has to get rid of what is irrelevant and distracting. I don’t think children perceive the flying Snowman, or the antics of the Red Balloon as magic, but possible and inevitable given the story.

The rights to adapt The Red Balloon became available in 1989. Mark was adamant that we should approach the construction of the musical in the same way as we would approach our work for adults. The only difference would be that the melodic material should be simpler - or at least we should try to anticipate what would be accessible to children, from our knowledge of the songs they sing.

Mark and I very rarely write together. We’ve done it once - with the title song of The Red Balloon. What happens usually is that I write the book and the lyrics and I hand them over to Mark. Mark then criticises them. He can be either supportive or vicious - always with a sense of humour, and he’s always prepared to listen. For example, in the first draft of The Red Balloon I wrote a long ballad about ballooning, for the old man with the beret to sing to Pascal in the rain as they meander through the streets of Paris. A few curt comments about my ode to the Montgolfier brothers from Mark, followed by some inarticulate gurgling from me, and it had been blue-pencilled. I don’t read music, and find it very difficult to make any informed criticism of Mark’s contribution. It usually amounts to nothing more than, “I don’t like that” or “I’ve heard that before”, “that’s just as I imagined it” or “that’s wonderful”. I try to indicate where I want voices and verses overlapping and Mark weaves the arrangements together.

There has always been the question of whether we should do it with child actors since half the characters are children, but two things have always prohibited this. Firstly, I would have to rehearse several teams of children to cover the number of performances planned for each production, and secondly it may be too tough musically.

Each production - this is the fourth - has been very different. Each has had new material, a new design and new choreography. I am still working on it and don’t feel in the slightest bit ashamed of this. It is reported that Lamorisse wrote 42 versions of the scenario before he was happy with it.

Anthony Clark adapted and directed The Red Balloon. Morning and afternoon performances until August 30 at the Olivier, National Theatre. Box office: 0171 928 2252