I’ve never claimed to have a great memory (well, not that I remember). But there is one moment I recollect vividly from school.

I am six or seven. I fall over in the playground, am led inside by teacher and ushered towards the staffroom. As she fetches the Savlon, the door stays open. The staffroom door! Reader, I cannot help but stare.

In retrospect, the secrets I learn are less than significant (it’s small; it’s dark; Mrs Power is called Valerie; Miss Ashford smokes Embassy). But it’s like seeing Mickey Mouse backstage at Disneyland, head on a peg, trousers round his ankles, chasing Tinkerbell round the canteen. I am intruding in a private place. I have believed teachers are perfect beings who never swear, argue or eat unhealthy snack foods. I’m sure Alfie thinks that today.

Fast-forward. Some weeks into parent-helping and I’ve yet to gaze into the secret depths of the staffroom. On my first day this is because I’m charged by my wife to find out who Alfie plays with and how his trousers get so dirty. Alfie’s playground behaviour is reassuringly banal. The most disturbing thing I see from the classroom window is adults drinking hot coffee from the kind of Tommy Tippee sippy-cup we tell our toddler he’s too old for.

The next week, I miss playtime altogether. It’s my own fault: we don’t finish our Amazonian rainsticks in time. (Not because we were messing about; more the inherent engineering challenge of recreating hand-crafted, centuries-old instruments out of Pringles tubes and an egg box.) But, in week three, there’s no escape. I work hard all morning, sit neatly in my chair, face the front with my arms folded - and realise Mrs Lewis probably didn’t mean me. As the children file out into the playground, I am ushered towards the staffroom for a cup of tea.

I feel uneasy. It’s not a place I should be. I still want to believe my children are being taught by perfect beings. I don’t want to see teachers with their heads off. But it’s OK. Visitors get tea together in the foyer, where there are comfy chairs, natural light, and a steady buzz of cheerful children bringing teachers’ sippy-cups in from outside, desperate to get a glimpse inside the staffroom. I make sure they don’t. For their own sakes.

Michael Cook is a freelance copywriter and a parent helper at Ernehale infants school, Arnold, Nottingham, which his children, Alfie and Poppy, attend