The real life original of the bestselling Harry Potter books emerged yesterday.

But like all the trainee wizards and witches of the author Joanne Rowling's childhood he has grown up and left the land of dark lords and merry pranks behind.

Ian Potter is now a damp-proofing technician in Yate, near Bristol. At the age of 32, with two children of his own, he is bashful about being reminded that he was once a trickster who used to put slugs on his playmates' picnic plates.

'It's true', he admitted. 'It's the way that slugs leave a slimy,shiny trail everywhere.Whatever you put the slug on, it leaves its mark.'

Mr Potter, a boy with 'a never-ending sense of adventure and mischief', and his sister Vikki were identified as a result of a brief remark in a rare interview with the writer whose third book broke sales records last week.

Ms Rowling talked of her games of wizards and witches in the village of Winterbourne, near Bristol. 'A gang of children, including myself and my sister, used to play together up and down our street.

'Two of the gang members were a brother and sister whose surname was Potter. I always liked that name."

Vikki, 31, a software company sales director, said: 'Our favourite thing was to dress up as witches. I think it's mad to have a hero called Potter but that's typical of Joanne. She was always getting ideas, and especially names, stuck in her mind.

'Ian was the perfect inspiration for a wizard. He was a nightmare, forever playing tricks.

'Once he told me, Joanne and her sister Di to run through some wet concrete which we did, totally unaware of the results.

'He used to do things like booby-trapping the stabilisers on my bike, and collecting tadpoles in jars and then plastering the green slime everywhere.

'He had this thing about slugs. When we had picnics, he was always hiding slugs on plates'.

Their father Graham, 61, who owns a motor company, said: 'He is OK now. But it has taken him 28 years to grow up'. Their mother Ruby said: 'In those days all the children who lived in the street used to play together outside. It wasn't just Joanne telling the stories.

'They all used to play story-telling games, because they did not have the games they have nowadays."

Ian said: 'I feel very happy for Joanne. I am pleased for anybody who can get something out of life doing something that they enjoy."