There was a time when pornography skulked in the shadows. It existed hidden from view, the territory of middle-aged men in mackintoshes. Only occasionally, in brief glimpses, did children come into contact with it. A peek at Page 3, perhaps, or, very rarely, the shocked discovery of torn pages from a “nudey mag” in the park.

But not any more. Pornography, it seems, is everywhere now. It lives in every house, clogging internet cables, tainting wi-fi connections, ready to appear on every computer screen and smartphone at the click of a button or swipe of a finger.

So saturated is society with pornography that UK prime minister David Cameron last month put forward plans to block access to online porn that would mean adults being forced to “opt in” if they want to view adult material.

The move is fraught with practical difficulties and has been criticised as censorship. But Cameron is risking the controversy because, he says, pornography has become so ubiquitous that it is “corroding childhood”.

With the growth of technology, the advent of smartphones and near- universal internet connectivity, it has become easy for children to view explicit and potentially scarring material. And more than merely stripping away the innocence of childhood, many experts and campaigners believe that access to online porn is actively corrupting young people, warping their morals.

A report published in May by the Office of the Children’s Commissioner for England, titled “Basically . porn is everywhere” - a rapid evidence assessment on the effects that access and exposure to pornography has on children and young people, shows a link between exposure to pornography and “high-risk behaviour” among children, such as having casual and unprotected sex.

More worrying, however, is the impact it can have on boys, particularly in regard to their attitudes towards sex and girls.

“We know that pornography is pervasive and that a significant proportion of children are exposed to it or are accessing it,” deputy children’s commissioner Sue Berelowitz writes. “We know that boys are more likely to view pornography out of choice than girls, who are much more reluctant viewers.

“Most worryingly, the evidence here shows that exposure to sexualised and violent imagery affects children . and that there are links between violent attitudes and violent media.”

Her words are borne out by the recent Steubenville High School rape case in Ohio, in the US. Two players from the school’s American football team, Trent Mays and Ma’lik Richmond, were found guilty in March this year of sexually assaulting a fellow student at a party. But more than that, the two young men were part of a group that took pictures and videos of the attack. And perhaps most chillingly, the pictures and videos were then traded among students, complete with messages either praising the assailants or admonishing the victim.

In one image, two boys are seen carrying their victim by her arms and feet as she hangs, seemingly lifeless, like a deer they are about to tie to the bonnet of their car as a hunting trophy. Far from showing shock at the images, students posted messages ridiculing the girl.

The callousness, the complete lack of empathy for another human being - let alone a defenceless 16-year-old - shocked the world and trained the global media spotlight on a hitherto unknown town in Ohio. It also forced teachers, parents and schools around the world to question what effect porn was having on the psychological make-up of students.

The way in which the images of young men repeatedly violating a girl as she lay unconscious were traded between students, like baseball cards or football stickers, brought this into sharp focus. One video taken that night showed a member of the group laughing at how “dead” the girl looked. In addition, reams of messages on Twitter and Facebook ridiculed the victim. Rape was treated as a joke; the girl was labelled a “slut” and a “whore”.

It was only when the girl in question became aware of the online bullying - “slut-shaming” - accompanying pictures of her on social media websites that she realised the full extent of what had happened to her. Then things moved fast. Her parents went to the police with a file of evidence taken from Twitter and similar sites.

The messages, pictures and videos uploaded and shared were eventually used as evidence in the juvenile courts to convict the two athletes. Sixteen- year-old Richmond was sentenced to at least a year in juvenile detention for rape, while Mays, 17, was found guilty additionally of distributing a nude image of a minor and told that he would serve at least two years.

But even after the pair were sentenced, one student took to Twitter to remark: “Remember, kids, if you’re drunkslutty at a party and embarrassed later, just say you got raped!”

Worryingly, this is by no means an isolated case. In fact, as the details of the Steubenville assault were being pored over, a remarkably similar incident came to light in Connecticut, where four members of Torrington High School’s American football team were arrested, this time for the statutory rape of two 13-year-old girls.

Within hours of the arrests, social networking sites were alive with comments from students attacking the victims: one of the girls was branded “a snitch”, while another tweet said, “Young girls acting like whores there’s no punishment for that, young men acting like boys is a sentence”.

For the overwhelming majority of onlookers, both cases are appalling. They reveal a moral collapse among a small group of young people, resulting in behaviour that many parents, teachers and schools thought their children were incapable of. Although very few are committing sex crimes themselves, too many seem unaware of what is unacceptable and only too happy to view and share the misdeeds of others.

Furthermore, the cases highlight a worrying separation between those parents, teachers and schools and the young people under their stewardship. These adults are just playing catch-up when it comes to how teenagers view sex and sexuality, both online and off it.

And this is certainly not a problem limited to the US. In April, for example, it was reported that in England, 15 students on average are excluded from school every day during term time for sexual misconduct; at least one of these will be between the ages of 4 and 11.

According to UK government figures, about 3,000 students were kicked out of school in 2010-11 for misdemeanours including sexual assault, sexual bullying and harassment.

Currency of shame

One such practice is “sexting”, where young people - almost always girls - are persuaded to share explicit pictures of themselves. Early research into the trend has revealed that it can have a devastating effect on those girls, particularly if the images go viral.

The phenomenon has been subject to particular attention in Australia, where young people taking part in the practice have even been charged with child pornography offences and placed on the sex offender registry.

Jessica Ringrose, a senior lecturer on the sociology of gender and education at the University of London’s Institute of Education in England, is a leading researcher on the subject of sexting and recently co-authored a report on the issue. She is currently working on a second piece of research looking at how sexting adversely affects girls in particular. The academic was one of the first to highlight the way in which some boys treat these images as collectibles, almost like football stickers, developing a currency that places greater worth on the more revealing images.

A common theme of Ringrose’s research is the fact that girls are denigrated for being “slags” or “sluts” among both boys and girls if they share pictures of themselves, even though they have often been coerced. Society’s expectation that girls should be pure and virginal is thrown back in their faces if they stray from the norm, even when they are forced or pressured into doing so.

“There is a male bravado about collecting pictures of girls, and they don’t appreciate that you shouldn’t distribute the pictures just because you have them,” Ringrose says. “But it is girls that suffer the most. Their sexual reputation is always on the line. If an image of them goes viral then it is the girl that is the one who is blamed. Often, the victim is the one that is cast as the slut.”

For Ringrose, the Steubenville case is a horrific extension of this. The young men, she believes, got a thrill out of documenting what they were doing to their victim, swapping images and trading comments. “And when the victim and her family went to the police, she was threatened by people in the town: they all treated her as if she were to blame,” she adds.

But what would lead school students to act in such a way towards one of their peers? Many campaigners in this field believe that early sexualisation, triggered by easy access to online pornography, is at the root of the problem.

In January, UK politician Diane Abbott spoke out about the “increasing pornification” of British culture, linking the rise of sexting and other forms of sexual bullying to the hyper-sexualisation of young people today. Fast-developing technology, she added, has led to a “secret garden, striptease culture in British schools and society, which has been put beyond the control of British families”.

Abbott’s comments can easily be transferred to any country in the Western world, and they express not just caution but fear: fear that too many young women are sharing intimate pictures of themselves with little thought to how damaging - mentally and socially - it could be if they went viral.

So what is to be done? The public response to the Steubenville and Torrington cases has been to ask questions of schools. Rightly or wrongly, the consensus is that schools should play a prominent role in teaching young people about ethics, morals and sexual health.

Ringrose believes that educators need to address rape culture and the normalisation of sexual violence in their schools, as well as teaching young people about sexual consent and respect. Indeed, perhaps the most worrying aspect of the Steubenville rape is that the boys involved - those guilty of the assault as well as those who filmed and photographed it - did not see it as a crime.

“Respect and sexual consent are among the most important areas that schools have to get across. Teaching that girls’ bodies can be treated like dolls which you can stick things in - as with the Steubenville case - is not OK,” Ringrose adds.

Chloe Combi, a UK journalist and author who was also a full-time teacher until last Christmas, has written extensively about the sexualisation of young people and the impact that easily accessed pornography is having on them. She believes that schools can do only so much and that parents need to be more involved in what their children are up to online.

“There were some cases of inappropriate images being shared when I was in the classroom, and I heard of one case of a film containing some nasty stuff that was shared on BlackBerry Messenger, but it is a relatively new thing,” Combi says.

“Kids are being told about the dangers of putting indecent images online in their personal, social and health education classes, and the police are often going into schools to talk about the legalities, but you have to consider that schools are seriously up against it in terms of time and how much they can realistically do. A huge responsibility lies with the parents,” she adds.

`Spotlight on the good’

In the wake of the arrests of four of her students, Torrington High’s principal, Joanne Creedon, attempted to intervene directly by issuing a letter to her students appealing to their better instincts and pointing to the education that they had been given at the school, to “get that spotlight on the good”.

“We need to make sure that spotlight is on us for your achievements large and small, for your acts of kindness, and for your service to the community,” Creedon wrote. “For those of you who do this every day - and there are hundreds of you - thank you. For those of you who don’t, get with the program. Do good.”

And she added: “We have provided you with the knowledge and the tools. It is up to you to make the right choices.”

But Torrington’s young football players did not make the right choices, and the problem of how to impart the sex education that will give students the knowledge and the tools Creedon speaks of is a fraught one.

Some point to the fact that in many schools “sex ed” is bitty, piecemeal or non-existent. It is perhaps no coincidence that the countries which are generally seen to have the best sex and relationships education and the lowest teen pregnancy rates - the Netherlands, Germany, Finland and the Scandinavian nations - are also those that scored highest in Unicef’s Report Card 11, the organisation’s most recent league table of child well- being in the world’s most advanced economies. Out of 29 countries, the UK came 16th and the US was 26th.

In the latter country, it is not uncommon for the abstinence-only approach to be the main strand of any sex education. A potentially more effective route, according to some experts, would be to put high-quality “gender ethics” in place early on in a child’s education, rather than push for sex education that might meet resistance from more conservative school systems.

The gender gap

R Danielle Egan, professor of gender and sexuality studies at St Lawrence University in Canton, New York, a leading figure on the subject of the sexualisation of young people, believes that gender inequalities are at the heart of the issue. She argues that the ready access to pornography that technology offers and practices such as sexting are symptoms of the problem, rather than the problem itself.

“There is no question that the media and popular culture have become more sexualised, which is having an impact on girls and women,” Egan says. “But it seems to me that rape culture is as prevalent in cultures where there is almost no sexualisation, such as Pakistan, Afghanistan and Congo.

“It is a much more deep-seated belief in culture and about girls, that they are objects of sex to be used, but then they are sluts if they show any sexualisation. More important is for society to eradicate the deep- seated idea that a girl’s body is fair game for sexual assault.”

It is a pressing issue, as another recent tragic case of bullying shows. This began as the result of an alleged rape and has since been dubbed Canada’s Steubenville.

Rehtaeh Parsons, a 17-year-old student from Halifax, Nova Scotia, was allegedly raped by four teenage boys when she was 15, one of whom, it is claimed, took a picture of the assault. In the days that followed, the image was widely distributed in her school and locally, and Rehtaeh was labelled a “slut” by her classmates.

According to a Facebook page set up by her mother, Leah Parsons: “Rehtaeh was suddenly shunned by almost everyone she knew. The harassment was so bad she had to move out of her own community to try to start anew.”

Rehtaeh became clinically depressed and checked herself into a psychiatric hospital. When her family eventually learned of her alleged assault, it was too late to collect physical evidence and the case came down to her word against the boys’. No charges were laid.

In April this year, Rehtaeh hanged herself; she survived but was left in a coma. A few days later, her parents agreed that her life-support machine should be turned off.

Leah Parsons blames Rehtaeh’s death on the boys she claims raped her daughter, their decision to share an image of the assault and the “bullying, messaging and harassment that never let up”.

Parsons, Steubenville and Torrington are not isolated cases, just the ones that caught the media’s attention. They are notable road signs in a world where, among some, rape is not only accepted but made light of, where the victim is teased, shunned and even condemned because she was unlucky enough to be in the wrong place at the wrong time.

Rather than seeing incidents such as these as the shocking exception to the rule, it is increasingly clear that schools, parents and teachers must catch up to the fact that porn is everywhere.