He sees that flash, the slight change in her expression and the way it quickly disappears. In turn, there is a slightly acknowledgement in his own features, a tiny quirk of his smile.

And yet his tone doesn't change, still friendly as ever, seemingly blissfully unconcerned or unaware of any change. "Exactly. I teach secondary school, so I have them through all of the fun teenaged years," he says. "They're mostly all good kids at heart, but of course there's all sorts of school drama and that sort of thing."