Three-quarters of teachers believe that easy access to hardcore porn through smartphones, the internet and other media is having a damaging effect on their pupils, a TES survey has found.
Responding to the poll, teachers described pupils who "couldn't get to sleep without watching porn", girls as young as 11 dressing like "inflatable plastic dolls" and boys who developed "almost pathological" attitudes to sex.
They also confirmed reports that children were feeling pressured to perform sex acts, using derogatory sexual language towards each other and developing warped views of sex and relationships.
The survey, which found that two-thirds of teachers felt that sex education was failing to keep up with recent advances in technology, was carried out as heads' union the NAHT called for lessons about the impact of pornography to be taught to children as young as 10.
The survey and the NAHT comments come in the aftermath of a TES feature on 5 October about the impact of porn on young people that triggered widespread debate.
A number of the 555 respondents to the TES research claimed that parents were "naive" about the amount of hardcore porn their children could access.
Teachers also complained that viewing porn led their pupils to become increasingly obsessed with body image and plastic surgery, with more than half saying they knew a pupil who wanted surgery to improve their looks.
They reported girls obsessed with make-up and tanning "to the detriment of study" and boys downing protein shakes in pursuit of the perfect body.
But teachers said the problem went beyond hardcore images: the hit erotic novel Fifty Shades of Grey and TV series such as The Only Way is Essex were also blamed for the increased sexualisation of the under-16s.
One teacher commented: "Children from as young as Year 7 are becoming over-sexualised. They feel under lots of pressure to perform sexual acts."
Another teacher added: "Very overly sexualised language is becoming the norm when speaking to each other, and more so about each other." Others claimed watching porn had resulted in "awful" behaviour of boys towards young women.
Another complained of "constant inappropriate chat, and shocking knowledge of strange sexual practices from younger pupils".
Kenny Frederick, headteacher of George Green's School in East London, said easy access to porn was a problem, even with strict controls on school computers.
"Our pupils have to hand in their phones at the beginning of the day so they are not viewing it in school, but you can't control what they do outside school," she said.
She said "sexting" - where pupils send photos of their body parts on their phones - was a particular issue of concern.
Lisa Handy, coordinator of the Sex Education Forum, said that young people were accessing porn to get "answers to their questions".
"If pupils don't have access to good-quality sex education, they go to other sources to get answers to their questions," she said.
"If they access things that aren't designed to educate it won't give them realistic information about what a healthy relationship looks like."
Nick Boddington, subject adviser at the PSHE Association, added that measures to block access to porn were "only part of the solution".
He said: "The sophistication of technology and young people's use of it makes such measures a significant challenge to implement.
"Therefore, it's important that pupils explore such issues and questions that relate to their safety and well-being gradually and age- appropriately."
The survey results were published as an explicit NHS sex education website for teenagers was accused by family values campaigners of encouraging "an unhealthy obsession" with physical acts.
Campaigners are calling for PSHE, which includes sex and relationships education, to be made compulsory in England.
Parents have the right to withdraw their children from any sex education lessons offered by schools.
Let ours be the voices that guide them
Alex McGrath, headteacher of Leighton Park School in Reading
These results demonstrate teachers' overwhelming concern about the damaging impact of pornography on our children owing to its immediacy, accessibility and graphic nature.
This screen-based generation, their teachers and parents need to be aware of the power of the devices in their hands. This is not simply about modernising our PSHE curriculum: it requires a whole-school approach to the burgeoning issue of the easy accessibility of porn to children, together with honesty and integrity in addressing the issue with young people themselves.
In 2003, teacher Jane Longhurst was murdered by a man with an obsessive interest in violent pornography, and her mother successfully campaigned for laws to regulate such material. However, in 2012, these laws have become outdated and will not protect our children from becoming victims or perpetrators. But the willingness of schools to educate passionately on this issue just might.
Our schools have a responsibility to the wider community and to produce young people who develop a moral compass during their time with us. It is not about telling children what to believe - they will suit themselves. However, when they do take choices throughout their lives at school and beyond, our consistent and clearly articulated values should guide them.
Schools' whole-hearted engagement with such values, living them in our everyday work, will go a long way towards responding appropriately to what is a very real problem.
Photo credit: Getty
Original headline: Hardcore porn is damaging our pupils, reveals TES survey