The signs are unmistakable: the long face; the slumped posture. Poor Simon.
He has the potential to be a good teacher. He is bright, organised and committed. He is popular with parents, who are pleased that he teaches their children. The students think he is great. They know that he cares and they enjoy his lessons.
However, he has one big problem - his head of department. Des is a deadweight, a miserable old curmudgeon who is slowly but inevitably dragging Simon down.
Every new idea is either rejected or marginalised. Des is scornful: "What are you doing that for? It will never work. Waste of time." An old man's mantra. Cynical poison.
Under such pressure, is it any wonder that Simon's enthusiasm is slowly draining away.
That professional responsibility to nurture and to encourage does not feature in the philosophy of Des. The old retainer who remembers the old days when things were so much better because you could give the kids a sly wallop and no one worried too much about your examination results.
If you had a child in the school there is no doubt about whom you would want to teach them. But it is really hard for Simon because he finds it impossible to distance himself from the atmosphere in which he works. It does have an effect; it would wear anyone down.
Of course, Des gets spoken to. No one avoids their responsibility entirely. It gets laid firmly on the line. His duty as a senior colleague ...
But it doesn't make any difference because he sees no shame in what he does. He isn't being obstructive, just realistic, because of course the kids in the school will always let you down. He doesn't want Simon to waste his time. He just wants to pass on his accumulated wisdom. And so it goes on.
When he gets back to the department he will mutter, or look, or raise an eyebrow, or scoff. When the door closes he doesn't change, because you cannot force someone to be a properly committed professional. If they don't feel it then it remains alien. And Des never quite does enough to bring the sky falling in on his head.
The man has had enough. He wants to retire and believes that a handsome pay-off is his birthright and that a conspiracy of quite staggering proportions is obstructing it. So he does very little. He no longer cares about the students he teaches.
Schools are small communities in which we all affect each other. These professional relationships might well be with people with whom you have nothing at all in common, other than work. But that doesn't matter because our work should show us that we have common goals and a commitment to develop our colleagues. We are the link between the past and the future and we need to accept this as a primary responsibility.
As far as Des is concerned, this is all crap. What matters is that he has been overlooked and underpaid since time began.
Simon has no choice. He has to move on to another school. For his own sanity as much as anything else. So the school will lose a teacher of the future and keep hold of one who has had his day.
Geoff Brookes is deputy head of Cefn Hengoed School in Swansea.