What is the moral distinction between allowing an accountant or a lawyer into a school to talk about career prospects to a class of 12-year-olds, and giving a military officer the same freedom to tell them about the Army?

According to the National Union of Teachers, one is useful advice, the other is propaganda. Yesterday the NUT debated a motion that stated that: “Teachers and schools should not be conduits for either the dissemination of MoD propaganda or the recruitment of military personnel.” The motion, not surprisingly, was passed. One should never underestimate the vacuous posturing of the NUT.

Strip away all the concern about “glamorising war” and it is clear from the debate that the very presence of military personnel in schools is anathema to the NUT. One delegate in a speech said: “Let's just try and imagine what that recruitment material would have to say were it not to be misleading. We would have material from the MoD saying, ‘Join the Army and we will send you to carry out the imperialist occupation of other people's countries'.”

If teachers cannot understand the difference between political opposition to the war in Iraq and the role of the Army in the defence of the realm, then pity the pupils they claim to teach. It is one thing to grandstand at an NUT conference about the so-called iniquity of an illegal invasion. It is quite another to undermine a profession, which is an essential pillar of the State, in front of a class of impressionable youngsters.

The timing is spectacularly inept. Barely a fortnight ago RAF servicemen in Peterborough were being advised to shed their uniforms before they went out on the streets, for fear of being exposed to insults and attacks. Recruitment is at a record low despite British troops in Afghanistan facing military action as intense as any since the Korean War. A recent poll suggested that only 23 per cent of the population is well informed about the Army and its role. One might have thought that, in these circumstances, teachers had a responsibility to redress the balance - to explain that the Army is there for society's protection, rather than as the unacceptable face of armed aggression, and to condemn the thugs who assault or insult young squaddies.

But if the teachers' role is questionable, what about political leaders? In Scotland last week, Alex Salmond chose the fifth anniversary of the invasion of Iraq to send out an egregious message that suggested that British troops stationed in Basra do not believe they should be there at all. “Their views about the rights and wrongs of conflict are very similar to the rest of us,” he claimed. There is a breathtaking arrogance about this - not only the assumption that his own views about the war are shared by the majority of the population, but that soldiers, whom he has never visited, have lost confidence in their role. It is also irresponsible. For the First Minister of Scotland to undermine the commitment of the UK's Armed Forces abroad does little to suggest that he has made the transition from left-wing gadfly to national leader.

This kind of view is, in truth, far closer to propaganda than anything that the earnest military officers who go into schools - always at the invitation of head teachers - seek to convey. They are there to explain the role of the Armed Forces, and these days, all too conscious of the delicacy of their position, they lay emphasis on issues such as citizenship and training for the future. They draw attention to the army values of courage, discipline, respect for order, loyalty and integrity; their motto is “inspire to achieve”. You can see why the NUT wants to eject them.

What the Army is offering is precisely the kind of structure that is so often lacking in the lives of today's generation of young people. Just over a year ago, I spoke to a 22-year-old who had returned with the Black Watch from Basra. He had seen one of his comrades killed by a roadside bomb; he had been in a tank that had narrowly escaped being blown up after a sustained attack from insurgents; he had lived through the blazing heat of an Iraqi summer. He was about as far removed from the Salmond caricature as one can imagine - he was proud of what his regiment was doing, defended the presence of British troops in Iraq and talked convincingly about the dangerous vacuum that would be created if they were pulled out.

But it was what he told me about his personal circumstances that struck me most forcibly. I asked him whether he regretted the years he had been away from home and his friends in Fife. Certainly not, he said - his only regret was that his time in the Army would, inevitably, be limited. “What might you have done if you had not joined up?” I asked. “I'd be in jail, nae doubt,” he said matter of factly. Among the kids he had grown up with, at least half, he reckoned, had dropped out of school early and taken to a life of crime. He had been saved by the Army, he said - it had given him not just an alternative, but also a way of rethinking his life.

Curiously, he was echoing a man who will certainly not be quoted by the NUT this week. The Duke of Wellington once explained how the Army introduced order into the chaos of young lives. “All the business of war, and indeed all the business of life, is to endeavour to find out what you don't know by what you do,” he said. “That's what I call ‘guessing what is on the other side of the hill'.”

Most head teachers, who welcome service personnel into their schools, will know what he meant. They should make it clear that teachers have a duty of care towards their pupils, and that includes presenting them with an even-handed picture of the relationship between a society and its Armed Forces. In previous times the Army has saved the nation from destruction. It may be called upon to do so again. Guessing what is on the other side of the hill is part of our history and should be part of our education.

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