Screen addicts: Children spend more time in front of a computer or television every day than they spend exercising every week

Addicted: A study has found that youngsters are spending more than four and a half hours every day looking at TV or computer screens

Children in Britain sit in front of a TV or computer screen for four-and-a-half hours a day, alarming research reveals.

Youngsters now spend an average of one hour and 50 minutes online and two hours 40 minutes in front of the television every day.

A report released by research firm ChildWise suggests that screens are increasingly turning into electronic babysitters and young people in the UK are spending more time plugged in than ever.

It found that children spend more time in front of a screen in one day than they spend exercising in the entire week.

The worrying research found that 97 per cent of 11 to 16-year-olds own a mobile phone – eight per cent more than the percentage of adults who own one.

And it showed that young girls have a voracious appetite for celebrity magazines such as OK! and Heat rather than more traditional teenage fare such as Jackie.

The study came as an academic warned that youngsters are using mobile phones to learn about each others’ bodies and access X-rated porn rather than learning about such matters ‘behind the bike sheds’.

Dr Emma Bond, an expert in childhood and youth studies, said adults ‘need to take our heads out of the sand’ about what is happening to young, impressionable children.

‘The research shows how children are using mobile phones in obtaining sexual material, developing their sexual identities and in their intimate relationships with each other,’ she added.

The Monitor Report 2010-11 found that children spent only two hours a week exercising in school, and taking part in physical activity out of school.

Two in three children aged between five and 16, and 77 per cent of children aged 11 to 16, have their own television or personal computer and, despite fears about online safety, almost half have internet access in their own room.

The study questioned almost 2,500 five to 16-year-olds about their computer, TV and reading habits. The findings show most go online daily and spend much of their time on social networks and video sharing sites such as YouTube.

But despite the popularity of the internet, the next generation is still likely to be one of telly addicts.

Around 63 per cent of children have a television set in their room but as the popularity of laptops increases and programmes are increasingly available online this is likely to drop.

'Your mother found this mobile under your mattress'

A spokesman for ChildWise said: ‘The number of children with a laptop or PC now matches those with a television but TV continues to play an important role. The way they are watching is continually changing. Children are seeking out programming that they want, when they want it.

‘Children’s online activity is moving towards personal access for all, so that, in the not too distant future the disadvantaged child will be the one without a laptop of their own.’

Despite Facebook supposedly being restricted to over-13s, more than two million children under that age now have a profile on the social networking site. It is named as their favourite website.

The research found a third of all seven to ten-year-olds visited Facebook in the last week, along with 71 per cent of 11 and 12-year-olds and 85 per cent of 13-16-year-olds.

Even with the wide choice from digital and satellite channels and dedicated youth stations such as ITV2 and E4, BBC1 remains the most popular TV channel.

EastEnders and The Simpsons are among their favourite programmes, along with the crude Channel 4 comedy about school life The Inbetweeners.

Margaret Morrissey of lobby group Parents Outloud, said children could not be blamed for spending time on the computer or in front of the TV.

On many housing estates gardens had been reduced to the size of a pocket handkerchief, she said. ‘We cannot complain as the generation in charge when they (children) use the things we have provided and don’t have space to do recreational things outdoors,’ she said.