"It's navy blue with a yellow pompom and ear flaps to stop him getting earache," says Hayden's mum. We are in the cloakroom area investigating the whereabouts of her Little Angel's woolly hat. This is not the first item from Hayden's extensive wardrobe of winter clothing to go missing. Two more woolly hats, several scarves, umpteen gloves and a green welly have similarly disappeared under mysterious circumstances.
I can tell by her tone that Hayden's mum suspects me of being complicit in the case of his lost belongings, but this is not true; the fact that he has misplaced two maths books and a number of class readers since the beginning of January supports the view that Hayden is easily distracted and frequently puts things in the wrong place.
"Do you remember the time he got a piece of wax crayon stuck up his nose?" I ask.
Hayden's mum looks long and hard at her Little Angel. When she turns back to me there is just the trace of a tear in the corner of her eye. "You don't think there might be something wrong with him?" she asks.
I smile reassuringly and explain that it's normal for those of a creative and intelligent disposition to misplace things: "I do it all the time; it doesn't mean there's anything wrong with the state of my mental health, now, does it?"
She gives me a questioning look, so I tell her the story of my missing diary. It is an item I have lost many times but have always recovered on account of it being fluorescent pink. On this occasion, however, it was nowhere to be found. Despite the offer of a substantial reward and several children spending their afternoon combing the school in search of it, its whereabouts remained a mystery.
At the end of the day all the likely suspects were gathered in the staffroom. "I definitely had it in here at lunchtime," I complained. "The only way it can have disappeared is if someone picked it up, presumably by mistake." I searched their faces for signs of guilt but found only sympathy and consolation.
Finally, Miss Marple rose from her seat. "Did you eat all your lunch?" she asked. "And I don't just mean the sandwich and the chocolate biscuit; I mean your apple, too?"
I hesitated at the randomness of her question before shaking my head. It is a well-known fact that I rarely eat my apple. "Then it is logical to assume that you returned said apple to the fridge. Ergo the case of the missing diary is solved," Miss Marple said. She opened the fridge door - and there it was underneath my lunch box, partially concealed by a tub of low-fat spread.
Hayden's mum and I decide to question her Little Angel further, but he appears to have misplaced himself. After a brief search we locate him back in the classroom, proudly wearing his missing hat. "It was in the paint cupboard," he says.
I smile. "Of course it was; where else would it be?"
Steve Eddison teaches at Arbourthorne Community Primary School in Sheffield