Do social networking sites affect your child's school performance?

Research has found that one in five parents believe that social networking websites are responsible for a decline in their children's school grades.

A poll by TalkTalk's internet security service HomeSafe found that children spend an average of around two hours a day on sites like Facebook, Twitter and Myspace, with 20% of 4,427 adults quizzed claiming it had contributed to a fall in school grades.

The survey also found that almost half of six to 11-year-olds spend up to two hours a day playing games online, but only one in 10 use the web to help with their homework.

Will Gardner, chief executive of Childnet, which aims to make the internet safer for children, said: "Children under the age of 15 have never known a world without the internet. It's revolutionised how they learn, play and communicate with each other.

"We are delighted that TalkTalk is offering this new Homesafe system and support the introduction and offering of such tools, at no cost to the user, that can really help support parents to parent online as well as off-line."