here are you from, surr?". With some unease, here at the site of the battle of Prestonpans, I answer that I have come from England. "What's England like? Is it crapper than here?" My interrogator is obviously interested rather than hostile, so I tell him that I prefer Scotland, that my ancestors are from the local area.
"England's just doon the road, isn't it, surr?", and I am treated to a graphic (at times incomprehensible) description of a bottle fight with some boys from Berwick, during the course of which, I realise, with some astonishment, that this 15-year-old has probably never been farther afield than Berwick-upon-Tweed, just half an hour down the A1. His geographical world is bounded by hostile communities.
"We dinna like Musselburgh or Pinkie, Port Seton's OK sometimes (Port Seton is less than a mile away), but if a boy from Tranent came through the door, he'd no leave alive."
I am very aware of my suit, tie and Barbour coat (bought cheap, I hasten to add, in an end of line sale), wondering how the apparent gulf in our social experiences can be bridged.
Curiously, the very enormity makes it easier. Even my accent doesn't trouble him, because I don't sound like a Tranent lad, and his defences are triggered by much more subtle differences than my middle-class Englishness.
It's no use trying to teach him maths, or science, since he leaves at Christmas, and is going to be apprenticed as a plumber, but we can talk. I enjoy DIY, and we discuss pipes and joints. He knows to a penny what different trades pay, and is interested in what supply teaching involves.
Under the hardman image is an unexpected gentleness: he shares a table with a girl who has made a Valentine's Day cake for her mum. Bored with money sums, he takes it from her, holding it high so she can't get it back. She grabs for it, kcking him hard in the shins.
"Who do you think you're kicking ?" he bursts out, and I brace myself for the confrontation. "You", she answers, with simple economy. I am wondering where the nearest principal teacher is, and what physical restraint I am allowed to use without being charged with assault, when he smiles, releases the cake with a cheery "All right then, hen", and sits down as though nothing had happened.
I realise in times like these that Wullie and his friends are neither aliens nor enemies, but human beings like myself. We may meet in an awkward context, but unless I back him into a corner, or tread on something sensitive, he wants us to get on.
Next year he may turn up to mend my washing machine, or reseal a punctured pipe, and I will offer him coffee and discuss the weather or the football as he works. I am puzzled by the relationships that school inevitably seems to force us into.
Education is a curious business. Are we really "casting false pearls before real swine" as I once heard it memorably described, or is it that our pearls have real value, but value that is too hidden and long-term for the majority in our increasingly instant culture?
I would not trade places with Wullie, and he, no doubt, would be equally horrified at the prospect of being me, but how do I set about persuading him that life can be wider and richer than tribal bottle fights? Perhaps I can't, perhaps the best thing I can do for Wullie is to give him the respect of talking and listening to him, of learning from him, as I hope he could learn from me.
Supply teaching is a strange existence. I am learning a lot, and shedding many of my preconceptions and fears. Meeting Wullie has been an experience I would not have missed.
However, it might still be wise not to push my luck: I will not be wandering around his particular territory on a Friday night.
James Torrance is a secondary supply teacher who recently returned to Scotland.