Over the past few years, there has been a drip-drip of artists defending old men who abuse their power over young boys and girls for sexual pleasure. It ranges from Alan Bennett's claim that a teacher who gropes his pupils can be the real child or true innocent, to the widespread assertion in Hollywood that when a 44 year old man drugs and anally rapes a 13 year-old girl, it is not "rape-rape". Indeed, Gore Vidal says the victim is "a young hooker".

Yet there is, largely, silence in response – and I realise I too have held off from writing this column several times. Why? Talking about this requires me to criticise some artists whose work I love, and it forces me to remember a period of my life I've tried hard to forget. But when I saw Alan Bennett's new play The Habit of Art at the National Theatre, I felt somebody had to say this.

I have no problem with artists sympathetically depicting the inner lives of paedophiles and pederasts; indeed, it can be a good thing. Every human being should be understood, and to understand is not to excuse. We should, for example, know that 70 per cent of child abusers have themselves been abused as children: it tempers the paedophile-bashing lynch mob, and forces us to look for humane solutions. It also helps avoid bad legislation like Megan's Law, which – by driving released offenders away from their families and friends and sending them into isolation – actually increases the number of children who are abused.

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What I object to is not the compassionate depiction of these men, but the claim that the victims are unharmed, or even enjoy it. This suggestion has featured in the work of several writers I normally admire. In Bennett's previous play The History Boys, a 50-something teacher called Hector routinely gropes his 17-year-old pupils' genitals – and they react either with flattered amusement, or by longing to be the next to be groped. The headmaster who objects is depicted as a prejudiced buffoon. The most sympathetic boy in the class – Posner – also grows up to be a pederast himself, who finds it hard to resist groping his pupils.

In interviews, Bennett makes it clear he is on Hector's side, saying: "I've been criticised for not taking this seriously enough. I'm afraid I don't take that very seriously if they're 17 or 18. I think they are actually much wiser than Hector. Hector is the child, not them." He added that good teaching is inherently "erotic".

In his new play, Bennett takes this analysis further. Benjamin Britten, the composer, is one of the main characters. He was sexually attracted to young boys – 13 was his perfect age – and throughout his life he picked out choirboys, gave them a special role in performing his music, and lavished adoration on them. According to the book Britten's Children, he appeared naked before them, snuggled with them in bed, although he didn't actually have sex with them. As with Michael Jackson, the parents seemed to know what was going on, and acquiesce.

Yet Bennett, in his introduction to the play, expresses only one problem with this. "A boy whose voice suddenly broke could find himself no longer invited ... which would seem potentially far more damaging to a child's psychology than too much attention." He also spares a thought for the "fat boys and ugly boys" who were never admitted to this sanctum.

This analysis also underpins Stephen Fry's play Latin!, which was published in 1992. It is set in a prep school where the central character, Dominic Clarke, is a teacher who "carnally violates" a 13-year-old orphan in ways one character says are "too vile, too diverse, for the sane mind to grasp."

Fry distills the tragic psychology of paedophiles with his usual brilliance. Dominic says: "When I was a boy, I thought, slept and played like a boy. Then nature began to drop hints about a change in status: a cracking voice, hairs about the buttocks, acne ... I never asked to be a man. I never wanted to be man. I want to be a boy. If when nature starts thrusting pimples and hairs through the skin, a boy could be kept from school and the world of men and just carry on behaving as a boy, then perhaps nature would give up and the pimples and hairs would recede. The permanent boy could be found."

This is precisely how the paedophiles I have interviewed in prison viewed themselves. And isn't it a description of what Michael Jackson tried to do? When seclusion didn't work, he turned to the surgeons to create the permanent boy.

But the play has a nasty sting. Dominic runs away with the 13 year old to live in Morocco. They write back to explain that there, young boys and men can live together as sexual partners. The school's pupils, en masse, demand to be allowed to live in Morocco. The plain implication is that these 13-year-olds were also longing to be abused by older men.

I know Bennett and Fry are wrong, because when I was a teenager, I was subjected to the persistent sexual advances of an older man in a position of authority over me. I managed to escape the situation without being abused, but I know other boys did not. There can indeed be an initial element of being flattered, or even excited – but it is also married to feelings of fear and revulsion that somebody who is supposed to have offered safety is offering danger. The adolescent is not in a position to make an informed choice. It is healthy for adolescents to explore their sexualities among themselves – but when an adult intrudes into this process, it can damage their sexual development with consequences for the rest of their lives.

I'm not interested in launching a hysterical attack on Bennett and Fry. I would like to appeal to their empathy – a quality they have demonstrated in so much of their work – and urge them to direct it not just towards Hector and Dominic, but also to their victims.

This can be a difficult topic to raise because the vilest slur against gay people has long been that we are closet paedophiles. The defence of Polanski showed there are plenty of straight people prepared to make excuses for abusing young girls, just as there are – alas – some gay people prepared to make excuses for abusing young boys. Yet this prejudice still crops up: recently, Richard Littlejohn accused Peter Mandelson of wanting to live on "the Rue Des Jeunes Garcons". It is, of course, nonsense: Mandelson is no more likely to want to have sex with a young boy than Littlejohn to have sex with a young girl.

But let's look back towards Britten. Or indeed to Oscar Wilde, who would (rightly) still be imprisoned today for having paying to have sex with very poor underage teenagers. Did the violent suppression of homosexuality perhaps have a deforming effect on their sexualities? When they were 12 or 13, they had a fleeting moment when they could explore their sexualities with other boys without shame – but it quickly slammed shut as they realised this behaviour was deemed immoral. Is this why they seemed to keep returning to 13 year olds in their fantasies as representing an idealised time of sexual freedom?

The taboos protecting young people from sexual abuse took a long time to build up. They have to be protected from erosion, because Alan Bennett is terribly wrong – the "real children" are never old men who want to cop a feel of adolescents.

j.hari@independent.co.uk