Across the room sits Chris, another bright little boy who tells tales. But his are known as lies. Chris pockets friends’ sweets and denies all knowledge of the heinous crime, or pushes someone in the playground and blames it on someone else, or tears up a classmate’s drawing and then proclaims his innocence when confronted. In fact, he’ll deny having done something even when there are dozens of witnesses. Everyone knows that Chris tells lies, and nobody trusts him much because of it.

Both Chris and David would have very long noses if they were wooden puppets. But, because they live in the real world, they have reputations instead. However, while David is known as a fantasist with a wild imagination, Chris has an image problem that would tax Max Clifford. Both boys are pedlars of untruths, but for different reasons. How teachers and parents deal with them is not straightforward. A London-based child psychotherapist argues that the most difficult task is making the distinction between fantasy and lying: “It’s an important one to make, even if there is a fine line between the two. You have to look at the particular situation: at what the child believes, at what is the motivation behind the story, at whether it is light-hearted tale-spinning or whether it is said with conviction. It is a question of degree and quality. ”

The fantasist may be trying to compensate for a troubled family life or feelings of inadequacy. The blatant liar may be acting dishonestly as a cry for help or because this is the way he sees his nearest and dearest operating. But just as important a factor is the child’s age. While three, four and five-year-olds are notorious for their tall tales (“Did you know that a tiger chased me all the way down the stairs yesterday?”; “That colour isn’t white, it’s black”), by the time children get to junior school they should have reached the developmental watershed of being able to admit when they have done something wrong. Of course, they will have also reached the irrefutable conclusion that when you admit you have done something wrong, you get punished for it.

A former primary headteacher from the Midlands is down to earth on the subject of how you deal with a child who avoids the truth, for whatever reason: “Every child at some point will look you straight in the eye and deny they have done something, even when they know they’re painting themselves into a corner. There is a strong pressure on all of us to lie in order to get out of trouble. ” His approach is to use intellectual comeuppance. He will sit the perpetrator down and talk him or her through the incident. He may bring in other children to help unravel the story. The more the better. Going over the incident so meticulously will cause the logic to fall apart - sooner or later.

It is crucial, he says, for teachers to use all the professional and personal skills at their disposal to avoid confrontation. Showing a child up is not the aim. “It requires gentle handling, particularly when parents are involved. It’s quite an ordeal for a parent to be told by someone that their child is telling lies. The reaction of many will be, ‘I know my child better than anyone else, and he wouldn’t lie’.”

Since a cursory flick through the Bible will show what an age-old sport lying is, it is a safe bet that the young fibbers in your class will continue spinning their stories. One strategy is what the retired head calls the pre-emptive strike: when a child brings something nickable into school to share with others, make it clear to everyone that it is hers, that she has brought it in to show them and that she will be taking it back with her at the end of the day. Thinking proactively is often the most direct way of thwarting the aspirant Artful Dodger.