Yet my heart sank at the media response to the sentence on Paul Ellis for the manslaughter of a child in his care on a school trip. “Jailing of teacher may spell the end of school trips,” said the headlines, and union leaders shook their heads, claiming that teachers will be deterred from running such trips .

That is an odd way to look at it. Are they suggesting that the only reason teachers currently agree to lead trips is that they know they won’t end up actually in jail if someone dies? That doesn’t wash.

We all know that the very worst thing is not the punishment, but the knowledge that in the cool judgment of a court you committed an act of irresponsibility that led to a child’s death. Whether it is prison, or community service, or a suspended sentence, that grief and horror is the same. A career is ended in disgrace. The hard thing to take is not a 12-month sentence, six with full remission - it is the pointing of the finger, the confirmation of guilt.

But there is another way of looking at the matter of poor Paul Ellis, and similar cases. You could argue that the terrifying conviction of teachers for negligence will underline, in the public mind, how rare and heinous such negligence is. It affirms the expectation from state and education authorities that the norm is responsibility, a high standard of care, proper local information taken in a professional manner, and common sense.

It is a signal that when teachers or other leaders take children into the wild environment for the vital business of outdoor education, a lot is expected of them. We do not expect them to bluster, to wing it, to make snap decisions to ignore the weather, to take their eye off the ball. We do not expect them to leave the safety rope in the car boot, or encourage children into a swollen stream that the locals warn against, or sit in the mountain cafe ignoring the dangerous japes of the ski group in the off-piste distance. We accept unavoidable tragedies, but we expect authority and vigilance.

And tens of thousands of times every year, that is what we get. That’s the point. When the finger is pointed at individual teachers who have individually failed in common sense (and there have been glaring, horrifying cases of just this) the heavy wrath of the law should reassure us that such failures are the exception.

Teachers’ representatives should not be hysterically defensive and predict the end of school trips. They should point out instead how many safe, happy, invigorating, life-enhancing trips there are, how clear the guidelines are, how careful the liaison with local professionals. They should express sorrow at the aberrations which led to conviction, and make it clear that these are abnormal. They do not represent the behaviour of the profession as a whole.

David Hart got it right when he said teachers should “stick with school trips - nobody will accuse them of negligence if they follow the guidance to the letter”.

What happened in Lancashire was a tragedy. The court decided, on careful examination of the evidence, that it was caused by Mr Ellis’ “negligence and foolhardiness”. It might well have decided otherwise; there have been cases in which courts have clearly said that nobody was to blame. Indeed, in one of these the pupil himself was blamed. One appeal found that an older teenage boy’s reckless and repeated disregard of clear orders was the prime cause of his injury, and the school was cleared.

The courts are not, as a rule, savage or vindictive or driven by a mawkish tabloid agenda; and careful teachers should not fear them.

I can see how hard it is, how very hard, for any compassionate colleague not to feel horrified fellowship for Mr Ellis. But he did what he did. For all his admirable remorse and his desperate efforts to save the child, his behaviour that day was not up to standard.

He knew it: he pleaded guilty, poor devil. But his failure and misfortune should not threaten school trips. There are standards. Sometimes they are breached, but we continue to expect them and most teachers meet them admirably. The occasional conviction underlines their existence.

I wish the poor guy was not in prison, but cannot be sorry he was found guilty. It strengthens, not weakens, the case for well-run outdoor education. If the court had said, in effect, “Oh well, there you go, these things happen - you can’t expect a mere teacher to know that a pool in that state was dangerous,” what parent would ever again send their child on a trip? As it is, they will.