You see, I know a great deal about Miss Lewis's private life. I know that last summer she got all giggly with the man who mows the lawn. I also know that when he leaned in through the classroom window to ask if he could plug in his Flymo, Miss Lewis went red. I know that half of Miss Lewis's class was convinced she was "affairing" the merry mower man. All of which left the girls more than a little surprised when Miss Lewis came back from her holidays engaged to a waiter from Thessaloniki.
This I know - and much more that I dare not divulge in a national newspaper - because Miranda has told me. Teachers are the raw material in an ancient core curriculum subject: applied gossip and total indiscretion. We parents get it at homework time.
"Mrs Cooper was sick today," I hear over the kitchen table. "That's the third time this week. Sally says she must be pregnant again. She went rushing out of assembly. And she did the same yesterday during human biology." "Maybe she's just not very well," I suggest. "Well Lucy heard her saying 'bloody men' to Miss Lewis. Why do you think she said bloody men, Dad?" I wonder if teachers recognise how much attention 30 girls can accord to their chance remarks. Maybe they've been rendered blase by all those years of marking exercise books and realising that no one in the class has understood a word. Some have certainly forgotten to be discreet, like the lovely Mrs Brown for instance.
Does Aurora Brown, as famous for her fiery looks as her forthright manner, have any idea how much my daughter's class took to heart her disquisitions on Mr Brown last year? Miranda still hasn't forgotten that if Mrs Brown had her time again she wouldn't end up married to Mr B, oh no. She also knows that bank managers are a waste of time because Mrs Brown also has a very poor opinion of her husband's profession and communicated it regularly during life skills last year.
Indeed I got the impression that public-spirited Mrs B spent most of her lesson advising any 10-year-old who'd listen that you should never marry a bank manager who can't put up shelves without the whole lot collapsing on his silly head.
All of which makes life potentially embarrassing for those of us who go to parents' evening with Mrs Brown - or have our account with her husband.
She is probably privy to a few of our secrets too. The fact that I have put on nearly a stone in the past 12 months is something that I have tried to keep quiet. Indeed the only reason why I am coming out of the over-tight closet now is that I recently read this fact discussed in Miranda's science book when they were doing a project on expansion rates. "Some things get bigger in water" ran the heading and underneath Miranda had written: "My Mum says that these days my Dad looks a lot bigger in the bath."
I'm glad to say Miss Lewis had tactfully kept the red ink off that one but even so I knew she knew more than was good for her. Or me.
So what do we do, we parents and teachers who stand on either side of the professional divide? The fortunate thing is that we do absolutely nothing. When the nation was listening to the Squidgygate tapes did not Princess Diana soldier on, waving and smiling regardless? In the same way people like us - parents and teachers - perpetuate the fiction that ours is a purely formal relationship. I don't enquire of Miss Lewis if she' s made it up with Zorba and she doesn't ask me if I need my trousers letting out again.
Which is exactly how it should be.
Adrian Mourby begins a weekly column in The TES on April 24