I had to take my baby to the doctor the other evening, and seeing as keeping a toddler quietly occupied in a crowded doctor’s waiting room is nigh on impossible, my friend bravely offered to have my toddler for supper. Unfortunately, this simple act of kindness meant that she would risk uncovering my deepest darkest mothering secret, hitherto only shared with my ever sympathetic health visitor. Oh well, it’s out in the open now anyway. Here goes: my toddler will only eat bread. I do not exaggerate. In my house it’s bread for breakfast, a roll for lunch, a sandwich for supper and that’s it.

You name the eating strategy, I’ve tried it. You name the book, I’ve read it. Name the parenting programme on whatever obscure satellite channel you like, I’ve watched it. My child will not eat anything except bread. When he was one, I passed it off as a fad. Then when my baby was born, I was secretly grateful that I only had to shove a bagel on his table and he was happy, but now, it’s impossible not to notice that my friend’s children are happily polishing off fish and chicken and vegetables, and mine is only happy with all things processed and carbohydrate.

So I confessed all to my friend, and she said that she’d sit him at the table with her kids, feed him what they were eating, and if it didn’t work, head for the bread bin. Good luck, I said, it won’t work. So of course when I got back an hour later, I was greeted by the sight of my eldest son sitting happily at the table, polishing off his second helping of pasta, fish and cheese sauce, with the fork that he’s always refused to use at home, looking like Annabel Karmel’s star pupil. It was then that it dawned on me. My 19-month-old is taking the living piss out of me. My friend, of course, couldn’t understand what all my fuss was about, as the little git happily helped himself to third helpings and then finished the food on her own children’s plates. “I promise you,” I told her, “he is not like this at home.”

Ah, that immortal phrase. How many times have I heard it, when I’ve sat down with some poor unsuspecting parent to try to explain that their beloved child is not the perfectly behaved pupil they may suppose. If they’ve been surprised, I’ve always been slightly suspicious. I’ve always just presumed that they were lying to cover the sins of their errant offspring, but now, having been successfully duped by my under-two, I’m not so sure. Could it be that my little cherub is actually a sneaky little bugger? If he can successfully manipulate me at 19 months into giving him a bread-only diet and then clock that my friend is unlikely to fall for the same trick, what hope do I have when he’s a teenager and wants to go out and smoke pot all night?

A mother’s love is a terrible thing. It can blind us to every one of our children’s little schemes and propel us to take their side unceasingly and see the best in them, whatever they do. Do mothers of convicted criminals have this as well? “He definitely is not like this at home, m’lud.” It’s a position I’m beginning to understand. Of course, since that momentous night round at my friend’s house, he has gone back to his old routine, and I am still keeping Mr Kingsmill in the style to which he has become accustomed.

“Starve him,” advises the health visitor. But I can’t do that, I’m his mother. I’m beginning to wonder if the whole fish and pasta and fork thing was just a figment of my imagination. If I hadn’t seen it myself I could swear my friend was lying. Because one thing is for sure, he definitely, definitely is not like that at home.

Gemma Warren is head of inclusion at a London secondary school. Email: gemmablaker@hotmail.com