After all, what are they after? They may talk about careers and training, but the unpalatable truth is that they are peddling a lie. The true purpose of the armed forces is to fight, but killing people is something that is never mentioned. They might talk about mechanics and engineering. They might talk about computers. But beneath it all is the hidden agenda of death.

They offer vocational training, apparently. But in what sort of context? A low loader carrying a tank has a lot of buttons and levers and costs more than pound;1 million. Men in uniforms are needed to look after it. You can wear that uniform. You can climb over walls, swing on ropes, get muddy.

You, too, can be shouted at by a bald man in big boots. But don’t mention the war. Don’t mention the blood.

Of course, some pupils in my school see it as a way of being paid to play exciting games with big toys. But they are never shown what the hard and shiny toys will do. People are soft and squidgy and the toys are designed to turn them into road pizza. But hey! That’s how things get sorted out, isn’t it? The armed forces, we are told, offer a vocational path for children from poorer homes. They can change lives, we are told. But is it militarism that does this? Or are any changes the consequence of belonging to something structured?

They certainly offer a simplified version of the world. All that stands between our perfect world and the forces of darkness are boys and girls with mud on their faces who have been taught to drive a truck across a field in the dark. In their world, you avoid making choices because someone else tells you what to do. You don’t have to be responsible. Of course, you will sacrifice your freedom, but any doubts you might otherwise have had are replaced by certainties and moral absolutes.

The rest of us know that the world isn’t a simple place. It is messy and rather disorganised. There are many sincerely held views that are different from ours. But they are just wrong. We don’t need to listen. We just need to polish the gun.

In spite of the lessons of history, we still accept the simple solutions to complex issues that the military mind offers. They don’t work, of course.

You think I am wrong? Well just go to Ypres in Belgium. There is no more fitting symbol of the absurdity of militarism. Each footstep across the five-mile-wide battlefield represents 35 bodies. All that potential drowned in mud.

But we still let them play their game and so they spend a lot of money to bring a tank to school. Join my gang, they say, and you can play with my toys. Let’s forget all the nonsense about careers and training. They need to trap young people from poor homes so that they will kill others under orders, without question. Yes, they will give you a job. For a while. Yes, they will give you some sort of training that may - or may not - have transferable skills. But you get it in exchange for agreeing to let others try to kill you.

We watch them smile and talk about careers, opportunity, national security, discipline. And does any of it make the world a safer place? Careers? Is that all that education has become? A way of providing our young people with the permission and the means to dismember others? Our silence in the presence of the machineries of death shames us all.

The writer is a deputy head in Wales. He wants to remain anonymous