Finding yourself between two men who are at odds with each other is complicated at the best of times, but when one is eight and the other is thirty-two it's ridiculous. You know when you're little, you probably have a toy which you absolutely love? Like your favourite teddy bear or a blanket? And then one day you go to look for it, but it isn't there? Well, that's how I felt about any dignity I had on that train.

I'm coming home from work. It's a long journey, so I see a lot of people come and go. But none like these two. Little boy with his mum, coming home from a pantomime, boards the train, sits down next to me, looks at the bloke on my left and realizes he has found an enemy. This isn't a normal thing, right?

But they don't know the meaning of normal. Kid starts coughing, trying to get the bloke's attention. Bloke tries ignoring him, stares out of the window at Loth's Academy, reads a brochure for Canterbury Zoo but this kid is very persistent. Until, in a very loud voice, "I think your beard is stupid."

Silence.

"Well, kid, I think you're stupid too." He smiles to himself, thinking this is over. But it really isn't.

"And why are you so short? People who're short are stupid, and I know that because you are short and have a stupid, stupid beard."

He's got guts.

"That's a bit rich, coming from you. You're still in primary school!"

"I bet you're so stupid because you never even went to primary school."

"And you've never been to secondary school."

"I'm still cleverer than you even though I've never been to secondary school."

"And the way you're talking you never will."

"But I don't need to."

"That statement disproves itself."

"That's stupid. It doesn't even make sense and it never will because you're so stupid you'll never go to secondary school."

By this point, we're no longer trying to stop them. When two people are stood up and screaming at each other you don't interrupt them. They stop when they stop, and anyone who forgets that will be in hospital for a lengthy stay. So we stay and watch them hurl abuse back and forth, getting more and more angry and baffling.

But, it can't last. You can hurl abuse all you like and it won't do any good. So now the two are, I'm amazed to say, wrestling. A fully grown man against an eight-year-old. More evenly matched than it might seem. The man's bigger and stronger, but the kid's quicker and lighter. But with people taking sides, there's only one option when a fight breaks out on a train.

"Prepare to depart at the next platform."