It was when one of the pupils screamed out loud that author Jeremy de Quidt knew his story was having a real impact.
Mr de Quidt's debut novel, The Toymaker, was written chapter by chapter for his weekly storytelling sessions at Wells Central CofE Junior School in Somerset.
Described as an "atmospheric, spine-tingling, adventure story with a dark heart", it has now been shortlisted for the 2010 Waterstone's Children's Book Prize.
"The first time I went into the school I didn't know what I was doing," said Mr de Quidt, 52, who did a year's PPA cover for Years 5 and 6. "I wanted to enthuse the children so I told them: "You can write about anything - 'Goldilocks and the Seven Dwarfs', 'Snow White and the Three Bears'. Then one kid at the front said, 'This is stupid,' and I thought he was right.
"So I went away and wrote the first chapter of a story for them. When I got to the end of the next lesson with them, they asked, 'What happens next?', and week after week it went on.
"I would spend the first part of the hour talking about what interested them, and end with the next instalment of The Toymaker. It was brilliant for them and brilliant for me. My debt to that school and that cohort of pupils is enormous."
Mr de Quidt had originally trained as a solicitor but gave it up in 1995 to become a writer. A few years later, after his wife Lizzie had their third child, the family moved from Oxfordshire to Somerset where the cost of living was cheaper and Mrs de Quidt went back to work full-time. However, in 2004, the book Mr de Quidt had been working on, a novel set during the First World War, was rejected.
By coincidence, Mr de Quidt had once helped out at his children's school working with an artist on a storytelling session about the legend behind a mosaic. When the school asked if he could come in to do storytelling sessions, he decided to give it a go.
Mr de Quidt's daughter Alice, now 14, was in Year 6. She told her dad that having him in her class was like having a "dangerous best friend - you didn't know what was going to happen next".
As well as testing out his ideas on the children, Mr de Quidt sent draft chapters to a friend living in Oxford for an opinion. She sent them on to David Fickling, the publisher who discovered Philip Pullman and Mark Haddon, who snapped it up.
Steve Turner, head of Wells Central, said: "Jeremy is a fantastic storyteller, brilliant and mesmerising. The whole point was to get children involved in storytelling and interested in books. It was a heaven-sent opportunity."
READ 'EM AND REAP
The nine shortlisted tomes for the Waterstone's Children's Book Prize
1. The Toymaker by Jeremy de Quidt (David Fickling Books)
2. Flyaway by Lucy Christopher (Chicken House)
3. The Great Hamster Massacre by Katie Davies (Simon Schuster)
4. The Girl Who Could Fly by Victoria Forester (Macmillan)
5. The Seven Sorcerers by Caro King (Quercus)
6. Love, Aubrey by Suzanne LaFleur (Puffin)
7. Desperate Measures by Laura Summers (Piccadilly Press)
8. Superhuman: Meteorite Strike by AG Taylor (Usborne)
9. The Crowfield Curse by Pat Walsh (Chicken House).