"Paedophilic interest is natural and normal for human males,” said the presentation. “At least a sizeable minority of normal males would like to have sex with children — Normal males are aroused by children.” Some yellowing tract from the Seventies or early Eighties, era of abusive celebrities and the infamous PIE, the Paedophile Information Exchange? No. Anonymous commenters on some underground website? No again. The statement that paedophilia is “natural and normal” was made not three decades ago but last July. It was made not in private but as one of the central claims of an academic presentation delivered, at the invitation of the organisers, to many of the key experts in the field at a conference held by the University of Cambridge.

Other presentations included “Liberating the paedophile: a discursive analysis,” and “Danger and difference: the stakes of hebephilia.” Hebephilia is the sexual preference for children in early puberty, typically 11 to 14-year-olds. Another attendee, and enthusiastic participant from the floor, was one Tom O’Carroll, a multiple child sex offender, long-time campaigner for the legalisation of sex with children and former head of the Paedophile Information Exchange. “Wonderful!” he wrote on his blog afterwards. “It was a rare few days when I could feel relatively popular!” Last week, after the conviction of Rolf Harris, the report into Jimmy Savile and claims of an establishment cover-up to protect a sex-offending minister in Margaret Thatcher’s Cabinet, Britain went into a convulsion of anxiety about child abuse in the Eighties. But unnoticed amid the furore is a much more current threat: attempts, right now, in parts of the academic establishment to push the boundaries on the acceptability of child sex.

A key factor in what happened all those decades ago in the dressing rooms of the BBC, the wards of the NHS and, allegedly, the corridors of power was not just institutional failings or establishment “conspiracies”, but a climate of far greater intellectual tolerance of practices that horrify today. With the Pill, the legalisation of homosexuality and shrinking taboos against premarital sex, the Seventies was an era of quite sudden sexual emancipation. Many liberals, of course, saw through PIE’s cynical rhetoric of “child lib”. But to others on the Left, sex by or with children was just another repressive boundary to be swept away – and some of the most important backing came from academia.

In 1981, a respectable publisher, Batsford, published Perspectives on Paedophilia, edited by Brian Taylor, a sociology lecturer at Sussex University, to challenge what Dr Taylor’s introduction called the “prejudice” against child sex. Disturbingly, the book was aimed at “social workers, community workers, probation officers and child care workers”. The public, wrote Dr Taylor, “generally thinks of paedophiles as sick or evil men who lurk around school playgrounds in the hope of attempting unspecified beastliness with unsuspecting innocent children”. That, he reassured readers, was merely a “stereotype”, both “inaccurate and unhelpful”, which flew in the face of the “empirical realities of paedophile behaviour”. Why, most adult-child sexual relationships occurred in the family!

The perspectives of most, though not all, the contributors, appeared strongly pro-paedophile. At least two were members of PIE and at least one, Peter Righton, (who was, incredibly, director of education at the National Institute for Social Work) was later convicted of child sex crimes. But from the viewpoint of today, the fascinating thing about Perspectives on Paedophilia is that at least two of its contributors are still academically active and influential. Ken Plummer is emeritus professor of sociology at Essex University, where he has an office and teaches courses, the most recent scheduled for last month. “The isolation, secrecy, guilt and anguish of many paedophiles,” he wrote in Perspectives on Paedophilia, “are not intrinsic to the phenomen[on] but are derived from the extreme social repression placed on minorities —

“Paedophiles are told they are the seducers and rapists of children; they know their experiences are often loving and tender ones. They are told that children are pure and innocent, devoid of sexuality; they know both from their own experiences of childhood and from the children they meet that this is not the case.” As recently as 2012, Prof Plummer published on his personal blog a chapter he wrote in another book, Male Intergenerational Intimacy, in 1991. “As homosexuality has become slightly less open to sustained moral panic, the new pariah of 'child molester’ has become the latest folk devil,” he wrote. “Many adult paedophiles say that boys actively seek out sex partners — 'childhood’ itself is not a biological given but an historically produced social object.”

Prof Plummer confirmed to The Sunday Telegraph that he had been a member of PIE in order to “facilitate” his research. He said: “I would never want any of my work to be used as a rationale for doing 'bad things’ – and I regard all coercive, abusive, exploitative sexuality as a 'bad thing’. I am sorry if it has impacted anyone negatively this way, or if it has encouraged this.” However, he did not answer when asked if he still held the views he expressed in the Eighties and Nineties. A spokesman for Essex University claimed Prof Plummer’s work “did not express support for paedophilia” and cited the university’s charter which gave academic staff “freedom within the law to put forward controversial and unpopular opinions without placing themselves in jeopardy”.

Graham Powell is one of the country’s most distinguished psychologists, a past president of the British Psychological Society and a current provider of psychology support services to the Serious Organised Crime Agency, the National Crime Squad, the Metropolitan Police, Kent Police, Essex Police and the Internet Watch Foundation. In Perspectives on Paedophilia, however, he co-authored a chapter which stated: “In the public mind, paedophile attention is generally assumed to be traumatic and to have lasting and wholly deleterious consequences for the victim. The evidence that we have considered here does not support this view — we need to ask not why are the effects of paedophile action so large, but why so small.”

The chapter does admit that there were “methodological problems” with the studies the authors relied on which “leave our conclusions somewhat muted”. Dr Powell told The Sunday Telegraph last week that “what I wrote was completely wrong and it is a matter of deep regret that it could in any way have made things more difficult [for victims]”. He said: “The literature [scientific evidence] was so poor in 1981, people just didn’t realise what was going on. There was a lack of understanding at the academic level.” Dr Powell said he had never been a member of PIE.

In other academic quarters, with rather fewer excuses, that lack of understanding appears to be reasserting itself. The Cambridge University conference, on July 4-5 last year, was about the classification of sexuality in the DSM, a standard international psychiatric manual used by the police and courts. After a fierce battle in the American Psychiatric Association (APA), which produces it, a proposal to include hebephilia as a disorder in the new edition of the manual has been defeated. The proposal arose because puberty in children has started ever earlier in recent decades and as a result, it was argued, the current definition of paedophilia – pre-pubertal sexual attraction – missed out too many young people. Ray Blanchard, professor of psychiatry at the University of Toronto, who led the APA’s working group on the subject, said that unless some other way was found of encompassing hebephilia in the new manual, that was “tantamount to stating that the APA’s official position is that the sexual preference for early pubertal children is normal”.

Prof Blanchard was in turn criticised by a speaker at the Cambridge conference, Patrick Singy, of Union College, New York, who said hebephilia would be abused as a diagnosis to detain sex offenders as “mentally ill” under US “sexually violent predator” laws even after they had completed their sentences. But perhaps the most controversial presentation of all was by Philip Tromovitch, a professor at Doshisha University in Japan, who stated in a presentation on the “prevalence of paedophilia” that the “majority of men are probably paedophiles and hebephiles” and that “paedophilic interest is normal and natural in human males”. O’Carroll, the former PIE leader, was thrilled, and described on his blog how he joined Prof Tromovitch and a colleague for drinks after the conference. “The conversation flowed most agreeably, along with the drinks and the beautiful River Cam,” he said.

It’s fair to say the Tromovitch view does not represent majority academic opinion. It’s likely, too, that some of the academic protests against the “stigmatisation” of paedophiles are as much a backlash against the harshness of sex offender laws as anything else. Finally, of course, academic inquiry is supposed to question conventional wisdom and to deal rigorously with the evidence, whether or not the conclusions it leads you to are popular. Even so, there really is now no shortage of evidence about the harm done by child abuse. In the latest frenzy about the crimes of the past, it’s worth watching whether we could, in the future, go back to the intellectual climate which allowed them.