The secret online vices of spouses are to blame for breaking up a growing number of marriages, lawyers said.

London - A rising tide of pornography is engulfing children from the age of eight on the internet, a teachers' conference heard on Tuesday.

“For many young people, pornography now precedes sex and many will have seen hundreds of strangers having sex before they have any sexual contact with another person,” Helen Porter, from St Gabriel's school in Newbury, Berkshire, told the Association of Teachers and Lecturers (ATL) conference in Liverpool.

Delegates demanded that teachers should receive specialist training in how to deliver lessons warning of the dangers of pornography.

Porter cited research from the London School of Economics which showed that 90 percent of eight to 16-year-olds had at some stage accessed pornography on the internet - many without meaning to.

“I know of a Berkshire schoolgirl who was persuaded to perform in an amateur pornographic video at the age of 13,” she added. “As a teacher of teenage girls and the mother of a teenage daughter, I am absolutely sickened by that thought. Unfortunately, younger children can stumble upon wildly inappropriate material by entering an innocent word into a search engine.

“Young people are unaware of the inevitable consequences of their sexual behaviour. A 15-year-old girl agreed to pose naked for her 18-year-old boyfriend. He took a few photos and they enjoyed looking at them together - just a bit of harmless fun. A month later, they split up and he was feeling low so he decided to email the photos to friends. You guessed it - they went viral and he ended up in court for distributing child pornography.”

James Shlackman, from Crosfields School in Reading, said imagery on the internet had changed significantly.

“Ten to 15 years ago, the sort of pornography that was available online was the sort of thing you could find in a top-shelf magazine.

“Today it is very different. Much of it is aggressive, some of it bordering on abusive. It doesn't show normal sexual behaviour but there is so much of it that, to young people without the benefit of experience, it appears to be normal.

“Young people today are being exposed to dangerously unrealistic portrayals of sex that, if emulated, may end up damaging the relationships they form both now and in later life.”

Alison Sherratt, a former ATL president and primary school teacher from Bradford, said primary school pupils were engaging in “a more explicit vocabulary and type of games”.

“We need to send signals to our colleagues in every staff room so they can tackle the subject openly and bravely to help our children retain their naïve and joyous childhoods,” she added.

Teachers were also concerned over the practice of “sexting” - sending sexually explicit photographs of fellow pupils. They want guidelines as to how they react to this. - The Independent