One in five parents in UK think their children’s school grades are suffering due to the amount of time they spend on social networking websites, a new study has found.

A questionnaire completed by 4,427 adults found that 20 per cent of parents believe their children ’s education is being hampered by the amount of time they spend on sites such as Facebook, Twitter, Myspace and other non-educational web pages.

The survey, conducted on behalf of TalkTalk ’s internet security service HomeSafe, found that children are spending an average of two hours and six minutes a day online.

Nearly half of six-to-11-year-olds spend one to two hours per day using the internet to play games, but only 10 per cent use the internet daily to do their homework, results show.

It found that 50 per cent of children aged between 12 and 17 use social networking sites every day while only 16 per cent use the internet daily for homework.

Childnet chief executive officer Will Gardner 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 one another.

“We are delighted that TalkTalk is offering this new 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 offline”.