It is summer term and the thoughts of our female teachers turn to Fifty Shades of Grey. "That's what my wife calls it," I tell them in reference to the patchwork of hairiness around the bottom half of my face.
Before anyone can respond, our headteacher appears. She is investigating reports that a scruffy-looking old man has been spotted wandering the corridors.
"Well, that's one mystery solved," she says, cheerily. "So, Mr Eddison, I see you're now sporting a beard."
I smooth down my bristles and smile winningly. Facial hair is in fashion at the moment, and the colour of mine is not entirely dissimilar to that of George Clooney.
"Some of the mothers couldn't keep their eyes off me this morning," I announce with a wink.
"They probably couldn't believe someone as old as you is still a teacher," laughs Miss Brightsmile, which is ironic because she looks far too young to be one.
"Just because I didn't want to join in your game of Duck, Duck, Goose, doesn't mean I'm no longer up to the job," I protest. "I have an arthritic right ankle; a terrible legacy from my sporting past. I used to play Sunday league football, you know."
Looking around, it occurs to me that the age profile of our staff has dropped dramatically over recent years. Later, I discover that this phenomenon is not confined to my school: according to a 2013 study by the Organisation for Economic Cooperation and Development, the UK has the youngest primary teachers in the developed world. Almost a third of them are aged 30 or younger.
Maybe they're conducting a witch-hunt against ageing teachers? Once upon a time grey hairs were revered as a sign of wisdom. Now they are nothing but symbols of physical degeneration, mental decline and an inability (or unwillingness) to use technology to maximise pupil learning. From now on I will keep a suspicious eye on the bright young things who have taken over our staffroom. In time I will discover what they really think of my generation.
Until then, I will rely solely on my pupils to tell it like it is. "Did you know you've got a beard, Mr Eddison?" says Ryan, who probably thinks I just forgot to shave.
"Yeah. How does it make me look?" I ask.
He reflects for a while as though it might be a trick question. "Really old.like about 42," he replies.
"I was hoping you would say that, Ryan, because I'm growing it to play the part of a very old man in a famous play called The Crucible."
He wants to know what it's about so I explain: "It's a true story based on some terrible events that happened in a town called Salem in 1692. Lots of people are accused of witchcraft and sentenced to death, and unfortunately my wife is one of them."
Light dawns. "Oh, so that's why you need a beard - because you're a wizard!" exclaims Ryan.
I put an arm around him and whisper, "Listen, don't repeat this in case it leads to a hysterical reaction, but my real name is Hairy Potter."
Steve Eddison teaches at Arbourthorne Community Primary School in Sheffield