Masquerading as a reporter from the City Echo, I sneak into an Islington junior school on an assignment to quiz a class of seven and eight-year-olds about a man called Charlie. My only leads are a sister, Hope, and that he’s lost his memory. Before we can print a story about a missing person, as a journalist I need to confirm the facts.

I’m an actor with Hope Springs Eternal, a theatre adventure project set up by Islington Green Community Arts in north London with St Luke’s Primary School. Funded by Paul Hamlyn and the Cripplegate Foundation, it’s based on a model by the Devon-based Theatre of Public Works.

The seven-day event involves a quest for a magic spring, draw-ing on local folklore around the curative properties of Islington waters. Team leader Ewan Forster and the company of performers help the project along, but it’s the children who are in control of the story. They discuss whom to trust, and whether to continue the quest. Their contributions are woven into the story.

They have decided that Charlie is a time traveller, who stowed away with Hope 150 years earlier on Cap’n Jack’s pineapple-laden boat. I attempt to unravel the plot with an excited class who rush to demonstrate water-divining rods, a treasure island map, a pineapple “planted” overnight (“I’ve got a clue in my tray!”) The drama fast assumes a reality of its own.

Dressed in saris, the children career into the playground to practise a water dance. Two men appear, one brandishing a pineapple through the railings. “Charlie!” they cry, greeting a long-lost friend.

Later, over a pile of half-glued costumes, the actors consider the children’s responses, in order to map out the mysteries to be discovered the next day. “A minority of the children believes wholeheartedly in the drama,” says Ewan. “The quizzical majority knows it’s about playing the game of believing.” The artifice is maintained throughout the week, he explains, in order to achieve the project’s main educational aim: the collective resolution of a conflict or moral dilemma, without violence. Children come and go, sceptical one minute, intrig-ued or immersed the next. The decision to play or not to play the game is crucial, and the company makes no stipulation that all must play at all times. Once the drama is over, the characters will return for a debriefing session, out of costume, so children aren’t left stranded in a world of fantasy.

During the rest of the week, the class invents lurid twists to the plot. For instance, is Hope a runaway or kidnapped child?

At the end, I’m lured by roars and screams to the end of the journey, enacted in a child-ren’s playground on the edge of the City Basin. Thirty excited children have just rescued Hope from the clutches of two evil hawks and reunited her with Charlie.

* Islington Green Community Arts: 0171 354 2015.