My son’s best friend isn’t his friend any more. It’s been that way for a while. I’ve noticed, gradually, in the school playground. Ex-best friend doesn’t look out for my son any more, doesn’t respond when he calls his name. Ex-best friend has other friends, high-value friends. For a while I wonder if I’m just being paranoid. Maybe that’s just what five-year-olds are like, I think, but no.

“It’s okay,” my son tells me. “He says I’m allowed to sit next to him on a Tuesday if no one else is there.”

Fuck that, I think.

“It’s not for him to decide where you sit,” I say. “Aren’t there better people to sit with anyhow?”

My son says yes but looks unconvinced.

My son is nothing if not resourceful. He finds other friends. One evening he sits down and writes invitation cards, asking his new friends to come and play. This weekend one of them came.

My son’s new best friend is charming. They get on fine, but I get that feeling they’ve been thrown together. In friendship musical chairs they are, for the moment, the ones left standing.

I don’t know why it is like that. It happens a lot and you can tell. Overnight my son appears to have lost an entire friendship group because one person does not want to be associated with him . He lists his friends: “there’s him … no, actually, not him any more, because he’s in ex-best friend’s group”.  Many classmates fall into that category. Ex-best friend has acquired some indefinable social value, a position of dominance that is, all of a sudden, just there. He’s not the brightest, not the biggest, not the sportiest, but he clearly has something my son doesn’t have. Or perhaps my son has qualities a five-year-old shouldn’t exhibit should he or she want to fit in. Or perhaps it’s a random, accidental configuration. It’s not entirely clear.

I’m not a teacher but as part of my job I visit secondary schools and sit in on lessons. Whatever the class, within moments of pupils entering the room, you can tell how the land lies, who leads the powerful group, who’s the outcast, which boy-girl pairing are the class golden couple, which pair have been left with each other by process of elimination. It’s not there all the time, but frequently I feel such a meanness in the air. The end of Key Stage Three in particular seems a time of exquisite cruelty. I invariably leave schools feeling glad I don’t have to go through youth again. It all looks horrendous and from what I remember, it was.

I was generally a “low value” person at school. My partner, from what he tells me of his experiences, fared better. Or perhaps he was just more successful at not giving a shit. Either way, I feel oddly responsible for whatever my son might go through. Could a lack of popularity be hereditary? Why can’t I find the words to give him that confidence that seems to conquer all?

Of course, it all fades. The cool people from school are all friends with me on Facebook these days, now that most of us are parents and none of us are cool. It’s as though things were always equal, but they weren’t. Children can be total sods and however innocent they appear, frequently their values – whether they’re based on the colour of your hair, the superhero on your lunchbox or something completely indefinable – totally suck.

My son is surprisingly stoic for a five-year-old. I know these things hurt him but he toughs it out. The worst thing is sensing the limits of what I can do and that I can’t live the next ten years for him. I hope I can make sure he always knows how brilliant he is. Sitting next to him on a Tuesday ought to be an honour.