In some cultures to this day it is considered normal for a young boy to go to a much older woman for his first sexual experiences. The idea is that she will be kind to him, soothe his anxieties and teach him some useful skills, so that he in turn will be kind and sexually skilful with inexperienced young women in his future.

Until recently in some circles rich boys were, and perhaps still are, taken by their indulgent fathers to a good-natured mistress or a friend of hers. Poorer boys might find themselves in the local brothel. Others might be initiated by a nanny, a governess or an older girl in the village or on the block.

I am not recommending this custom. I would not like to be seen as someone who actively encourages young boys into the arms of prostitutes, no matter how refined, or of friendly amateurs either, no matter how kindly. It just seems absurd to me, when the world is full of so much truly terrible evil, to feel particularly morally outraged when something of the sort happens — especially in a country where you can see young people wriggling in the throes of reality TV sex, or read the confessions of the bonking-mad every day in the tabloids.

Yet in our hypersexualised culture there was shock, horror and disgust last week when 32-year-old Hannah Grice was found guilty of having had a six-month affair with an apparently very willing boy of 14; she pleaded guilty to two specimen charges of indecent assault, but what she was really in the dock for was having sex with an underage boy. Of course what she did was illegal. Of course most people would think it was morally wrong. But I do very much wonder whether she deserved the extreme condemnation and the extreme punishments visited on her.

The devil lies in the detail in such cases. The degree of wrong depends on the circumstances, which in this case I know only from court reports. This woman was a teacher and married, with two young children; many of her crimes were committed in the matrimonial bed and they were persistent. She was a friend of the boy’s parents but abused their trust, as well as her unhappy husband’s.

On the other hand, she was not this boy’s teacher herself; she did not breach that trust, which would surely have been very much worse. Nor, it seems, did she seduce him in the ordinary sense of the word. Perhaps legally speaking she did, but it seems that he developed a crush on her and, even if he may initially have been reluctant, he was willing.

As an underage person he could not legally have consented, but it seems that in everyday understanding he did. I don’t know — and it is an important detail — whether she was in some way predatory or had some powerful psychological hold over the boy, so that he was not as willing as it might have appeared. However, over a period of many months he regularly went to meet her, which suggests at least a degree of free will.

Boys of 14 vary; with puberty beginning earlier these days, many of them are sexually mature young men, suffering not from shyness but from sexual longing.

In any event, the wretched woman has been sentenced to 15 months in jail. This seems extreme, especially as she has also been put on the sexual offenders’ register for 10 years and has naturally been sacked from her teaching job. Her career is over, her name is mud, her family is in shock and, as a sex offender, she will find it very difficult to get other work. This alone is severe punishment, even without a jail sentence. And 15 months is a long time in a British prison.

There is something very odd about this case, given what’s happening to prison sentences. Generally speaking, the government and the judiciary seem determined to send fewer, not more, people to jail. In January this year the Home Office announced legislation under which judges and magistrates will have to take prison overcrowding into account when sentencing, because the jails are already full to bursting. Paul Goggins, the correctional services minister, said that offenders would receive effective punishments while ensuring that prison was reserved for the most dangerous and persistent offenders — not, one might think, a category that Grice falls into.

What is more, only last Wednesday Lord Woolf, the lord chief justice, called for changes to sentencing that would put fewer criminals in jail. He said prison should be reserved only for the worst crimes, such as murder, violent assault and white-collar offences, and also fine defaulters. “While I firmly believe,” he said, “that for serious and violent crimes there is no alternative to a custodial sentence, I also believe passionately on taking steps to turn people away from crime . . . One major challenge is to convince the public that non-custodial sentences do provide a satisfactory punishment to offenders.”

This must ring hollow to Grice. Although I am sceptical about community penalties it is quite absurd in the current climate of opinion in the Home Office and judiciary that a woman who is unlikely to reoffend, and who has already been severely punished in non-custodial ways, should be given a serious prison sentence as well.

Double standards seem to be at work here. Compare the sentence given in 2004 to Phillip Carman, the GP who indecently assaulted several women patients in his surgery in the most flagrant breach of trust and abuse of a doctor’s authority. He was sent down for a year, three months less than Grice. The judge said that Carman had been punished enough because he had lost his standing in the community. Admittedly, his sentence was later increased to 18 months by another court — but that is still only a bit more than Grice’s term.

Or compare the sentence for a drunk driver who knocked down and killed a young girl on Christmas Day; in 2004 his sentence was reduced to five years by appeal court judges. They said their decision followed a ruling by Woolf, who recommended four to five years where the offender pleaded guilty and showed remorse.

Where is the logic in any of this? However badly Grice has behaved, she is simply not in the same league as a drink-driving killer, a sexually abusive doctor or men who abuse babies. The law is not always an ass, of course, but in this case it does appear to have been both a bit of an ass and a bit of a misogynist prig, as well.

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