Computer retailer PC World launched a Children's Charter today, committing to offering free child security services for all PCs it sells to parents.

The service provides parents with advice on how to use the security features of Microsoft's Vista operating system and Symantec's Norton 360 internet security software to limit the time children spend online and monitor what they access.

Using this information it is hoped that parents can stop children 'accidentally' stumbling across pornography sites, or chatting with strangers on instant messaging software and in open chatrooms.

Parents buying a PC or laptop will be offered the service at the point of purchase, or in-store collection if they bought online.

The commitment applies retrospectively to all Vista PCs which PC World has sold to parents since 30 January this year.

New PCs bought under the scheme will also have Childnet's Know IT All software installed, which provides a guide for parents to keeping their children safe online and encourages parents to become more involved with their children's online activities.

"Alcohol, cigarettes and films all come with age restrictions enforceable by law, but PCs and the internet do not," said PC World managing director Keith Jones.

"This is not a sensible or sustainable situation and we believe our Children's Charter will make the internet a safer experience for what is the first truly digital generation."

All the technical elements of the service are already installed on PC World's PCs which have Windows Vista and Norton 360 installed.

But parents will be offered a free set-up service by PC World staff when they buy a PC or laptop, including instruction on how to administer the security features.

PC World has enlisted GMTV presenter Lorraine Kelly, who has a 13 year-old daughter, to publicise the Charter.

"Parents know that the internet is a great educational tool but they also know that it has a darker side," said Kelly. "Anything we can do to protect children while they are online, we should."

A survey conducted by PC World found that 75 per cent of parents would be interested in tracking their children's activities online, but that their children are often more tech-savvy than they are.

Mary Louise Morris, head of education and awareness at Childnet, believes that this lack of technical skills means that parents often abdicate responsibility for their children online.

"When we meet with parents, they want to know what the police, schools and ISPs are doing to protect children, but ultimately it comes down to the responsibility of individual parents," said Morris.

"This service and Childnet's software will enable parents to make their children safer on the internet in the future."

A recent European Commission study of children's online activities across 29 countries showed that children were aware of online dangers and were fairly astute at dealing with them.