Jonathan Bishop (.org.uk)

First they targeted glamour model Imogen Thomas before attacking fellow Welsh celebs Katherine Jenkins and Gareth Thomas.

And now cyber-bullies have abused football legend John Hartson and led him to quit social networking site Twitter.

The former centre forward is the latest high profile Welsh celebrity who has become a victim of sickening online outbursts prompting calls from anti-bullying campaigners and internet experts for “serious action”.

Such is the level of abuse aimed at Hartson in the past few months that he has been forced to quit Twitter last week.

The 36-year-old, who had nearly 125,000 followers tweeted: “I’m sorry to all my genuine followers but I shall be coming off Twitter in the next 48 hours! I have my own reasons for doing so.”

In July last year the former Celtic striker was taunted about a dying 11-year-old cancer sufferer he had befriended.

Hartson, who himself fought cancer, was left outraged when someone posted a string of twisted sectarian messages about terminally ill Jordan Houston.

Earlier this month he also slammed a Twitter troll who told him to “drop dead”.

Keith Towler, the Children’s Commissioner for Wales, said his office had seen a steady rise in the number of people seeking advice about online bullying and described the issue as a “sleeping giant”.

He said cyber-bullying was much harder to stamp out than physical bullying because of the constant development of new technology.

“In my generation bullying was something you associated with the school playground, it was something which happened at the school gates and something you could leave behind when you went home,” said Mr Towler.

“But now, what children and young people talk about is that it’s much more 24/7 because of modern technology.

“If we are to ensure children are kept safe then parents first need to realise the extent that their child is using the internet everyday.

“Parents need to become more savvy themselves about the technology and that way the necessary safeguards can be put in place.

“We need to ensure children can feel safe when using these modern technologies in a way which will not prevent them from the fantastic benefits they provide.”

Internet expert Jonathan Bishop, who runs the Crocels Trolling Academy, part of Swansea University’s Institute of Life Sciences, said the police should be more proactive in addressing harassment online.

“As it is, it’s all too easy for someone to abuse someone without any repercussions,” he said.

“When you think that councils can use things like the Regulation of Investigatory Powers Act to snoop on whether parents applying to schools are in the right catchment area why can’t the police use it to find these perpetrators?

“There is a lot people can do to combat cyber bullying but ultimately the responsibility lies with the websites and they are not taking the issue seriously enough.

“There are loads of tools available to people – such as software which has filters for social networks which allow you to block any person you want – but people don’t always know it’s available and don’t know how to use it.”

Des Mannion, NSPCC national head of service for Wales said: “Any online bullying is offensive and demeaning and should be stamped out immediately.

“Bullying in all forms causes misery for thousands of children and is one of the main reasons children contact ChildLine.

“Twenty-four hour internet access and an increased use of mobile phones means that cyber bullying is on the rise and young people can be abused by text, email or social networking sites in their homes.”

He added children and young people who need to talk can contact ChildLine, the UK’s free, confidential 24-hour helpline, on 0800 1111 or visit childline.org.uk.

First they targeted glamour model Imogen Thomas before attacking fellow Welsh celebs Katherine Jenkins and Gareth Thomas.

And now cyber-bullies have abused football legend John Hartson and led him to quit social networking site Twitter.

The former centre forward is the latest high-profile Welsh celebrity who has become a victim of sickening online outbursts prompting calls from anti-bullying campaigners and internet experts for “serious action”. Such is the level of abuse aimed at Hartson in the past few months that he has been forced to quit Twitter last week.

The 36-year-old, who had nearly 125,000 followers tweeted: “I’m sorry to all my genuine followers but I shall be coming off Twitter in the next 48 hours! I have my own reasons for doing so.”

Last July the ex-Celtic striker was taunted over 11-year-old cancer sufferer he befriended.

Hartson, who himself fought cancer, was left outraged when someone posted a string of twisted sectarian messages about terminally-ill Jordan Houston.

Earlier this month he also slammed a Twitter troll who told him to “drop dead“.

Keith Towler, the Children’s Commissioner for Wales, said his office had seen a steady rise in the number of people seeking advice about online bullying and described the issue as a “sleeping giant”.

He said cyber-bullying was much harder to stop than physical bullying due to constant new technology.

“In my generation bullying was something you associated with the school playground, it was something which happened at the school gates and something you could leave behind when you went home,” said Mr Towler.

“But now, what children and young people talk about is that it’s much more 24/7 because of modern technology.

“If we are to ensure children are kept safe then parents first need to realise the extent that their child is using the internet everyday.

“Parents need to become more savvy themselves about the technology and that way the necessary safeguards can be put in place.

“We need to ensure children can feel safe when using these modern technologies in a way which will not prevent them from the fantastic benefits they provide.”

Internet expert Jonathan Bishop, who runs the Crocels Trolling Academy, part of Swansea University’s Institute of Life Sciences, said the police should be more proactive in addressing harassment online.

“As it is, it’s all too easy for someone to abuse someone without any repercussions,” he said.

“When you think that councils can use things like the Regulation of Investigatory Powers Act to snoop on whether parents applying to schools are in the right catchment area why can’t the police use it to find these perpetrators? “There is a lot people can do to combat cyber bullying but ultimately the responsibility lies with the websites and they are not taking the issue seriously enough.

“There are loads of tools available to people – such as software which has filters for social networks which allow you to block any person you want – but people don’t always know it’s available or how to use it.”

Des Mannion, NSPCC national head of service for Wales, said: “It’s offensive and demeaning and should be stamped out immediately.

“Bullying in all forms causes misery for thousands of children and is one of the main reasons children contact Child-Line.

“Twenty-four hour internet access and an increased use of mobile phones means that cyber bullying is on the rise and young people can be abused by text, email or social networking sites in their homes.”

Children and young people who need to talk can contact the free, confidential ChildLine 24-hour helpline, on 0800 1111 or visit childline.org.uk.

More than 330 incidents of cyber harassment and bullying were investigated by South Wales Police this year, according to a Freedom of Information request.

The figure includes incidents of abusive, threatening or harassing messages sent via social networks to teenagers as young as 14.

The Child Exploitation and Online Protection (CEOP) Centre is currently running a programme called Thinkuknow to warn children and young people that abusing people online – or trolling – is a crime.

A spokesman said: “Too few people realise that in acting this way online you can quickly break the law.

“People may think they can remain anonymous when they are online, that they can say and do things they wouldn’t dream of doing in real life without consequences.”

Jonathan Bishop, a South Wales based internet expert who recently ran a Trolling Academy tutorial, said fixed penalties and ASBOs should be used against cyberbullies.

Mr Bishop, a town councillor for Treforest, said the use of false identities is a “serious problem”.