By Chris Page
Producer, BBC Radio Five Live Report
Stephanie Godwin found her problems continued at home
A recent survey of school pupils estimated one in ten has admitted sending an abusive e-mail or text. The new form of harassment is causing misery to hundreds of schoolchildren but BBC Five Live Report found it is difficult for parents, teachers and anti-bullying groups to stop the cyberbullies.
There is a stereotype of what a school bully looks like - you'll probably think of Grange Hill's Gripper Stebson, who used his size and strength to intimidate victims who were much smaller than he was.
But bullying has gone online.
It is a disturbing new twist to an age-old problem - bullies are turning to text, the web and instant messaging to bring misery into their victims' homes.
Thirteen-year-old Stephanie Godwin from Gloucester is now having her lessons at home after bullies turned on her.
She was being picked on at school - but the torture continued even after she left to begin her home schooling programme.
"They were sending me horrible messages over MSN, and sending me e-mails through my website every day," she says.
Stephanie has kept a record of the messages she was sent.
One reads: "Gay! Ur ********* fat cow and a fat *****. U wanna shut ur ******** mouth cos u is gonna get banged."
Stephanie's mum Debra has now started a website and support group, All Schooled Out, to help other people in her situation.
She is adamant that schools and the government need to do more to tackle cyberbullying.
"It's all very well having an anti-bullying policy in print, but it needs to be acted upon, and it needs severe measures. The computer was designed for better things."
A recent survey by MSN - part of the Microsoft company - found that 1 in 20 teens admitted being involved in online bullying.
Two-thirds said they knew someone who had been cyberbullied.
Jon Carr, new technology adviser for the children's charity NCH, is one of the country's leading experts on cyberbullying.
"The kind of messages I've seen range from 'you're big, you're fat, you smell,' through to 'we know where you live, we're going to burn your house down'," he says.
He insists it deserves to be treated as seriously as verbal and physical bullying.
"Bullying is subjective - what one child might be able to laugh off, another kid might find extremely distressing.
"It magnifies the problem and spreads it to literally audiences of tens of millions.
"So the sense of embarrassment and hurt grows accordingly."
Another charity, Parentline Plus, says its research shows cyberbullying affects girls much more than boys.
"Boys' bullying is all in your face, it's gang oriented, it's often physical," says Jan Fry, Parentline's head of policy.
"Girls are much cleverer. It's subtle, underhand and very difficult to detect."
Some schools are turning technology on the bullies.
Hundreds have bought monitoring or blocking software to detect unpleasant phrases circulating on the school network.
Teachers are setting up services which allow pupils to report bullying by text.
A support group has been set up for victims of cyberbullying
But experts agree that while technological solutions are valuable, cyberbullying can only be tackled with a concerted effort involving parents, teachers and kids too.
The Children's Commissioner for England, Al Aynsley-Green, says children should not forget they have an important role.
"People often think bullying just involves the bully and the person being bullied, but the bystanders can make a big difference, particularly if they're in an internet chatroom," he says.
There is also concern that parents need to learn more about cyberculture.
MSN UK's Head of Citizenship Natalie Mead says: "Nearly half of the parents we spoke to didn't know about cyberbullying.
"That means we have a big chance to educate them about this sort of stuff."
The police have been involved in cyberbullying cases.
"Kids who engage in cyberbullying are taking an enormous legal risk," says Alastair Kelman, a barrister and internet expert.
"The normal offences you have for causing distress to people will cover this, and victims could also use the law of defamation."
But for many victims, the thought of speaking out at all is a scary prospect.
Stephanie Godwin says she is getting over her bad experiences - and she says people shouldn't be frightened of bullies, whether they're online or not.
"They're just sad. That's as nice as I can put it."
Five Live Report: Cyberbullying can be heard on Radio Five Live on Sunday 16 April at 1100 BST and 1930 BST and will also be available at the Five Live Report website