Children are easily able to access pornographic videos on their mobile phones with parents only finding out when the bill comes to them.
The National Association of Head Teachers says mobile phone pornography in schools is now “widespread and very worrying”.
One school is confiscating four mobile phones a day because of pornographic images on them, according to a national newspaper.
The safeguards mobile phone companies have in place to protect children from pornography on phones are not working, the paper reports.
The Daily Mail says pornography under headings such as “More Fun Stuff!” is available for anyone to view.
The content can cost as little as £1.49.
The newspaper highlights the case of one eleven year-old boy who ran up a bill of £500 after viewing a pornographic website.
Kathy Young, his mother, said: “The first I knew about it was when Alex was sent a text telling him he was over his credit limit.
“I checked my bank account and was astounded to see the amount that had been deducted.”
The mobile phone company Vodafone claims to have an automatic bar on access to 18-plus material.
Orange said they have a similar barrier, which could be released by calling the customer services department.
But the newspaper says the restrictions are simple to bypass without any age checks.
Earlier this year it was reported that more than a third of teenagers have received indecent sexual images by text message or email.
Over a third of the 2,094 young people in a study carried out by children’s charity Beatbullying said they had received a sexually explicit text or email.
‘Sexting’, the sending of messages with sexually explicit content, is also leading to images being placed on social networking websites.
In August research was highlighted showing that, in 2005, 93 per cent of boys had viewed pornography by the age of 18.
Oliver James, writing in The Guardian, said that with the rise of free websites that figure would now have increased.