A generation of "multitasking" children are living their daily lives - including eating and falling asleep - to the accompaniment of television, according to a survey of youngsters' media habits.

The flickering of the screen accompanies most of them before they go to school, when they return home, as they consume their evening meal and then - for 63%, far more than read a book each day - in bed at night. The study of five- to 16-year-olds shows that four out of five children now have a TV set in their bedroom.

So ubiquitous has television become that many children now combine it with other activities, including social networking online, flicking their eyes from laptop to TV screen and back again. Even if they are focusing on the television, young people are now reluctant to commit to one programme, with boys in particular often flipping between channels to keep up with two simultaneous shows at once.

The findings, from the market research agency Childwise, will fuel concerns that childhood is increasingly about private space and sedentary activities and less about play, social interaction or the child's own imagination.

The government's recent Children's Plan, while attempting to calm panic over claims of "toxic" childhood, focused on improving play facilities as a means of ensuring a more balanced life for screen-bound youngsters.

Today's survey findings indicate a revival in television-watching among children after three years of decline, driven mainly by more girls watching soaps such as Hollyoaks and EastEnders.

Internet use - now that the social networking bug is biting younger than ever - is also continuing to grow at a far greater rate than the brief fall-off in TV viewing. That means British children spend an average of five hours and 20 minutes in front of a screen a day, up from four hours and 40 minutes five years ago.

The rise may have come at the expense of reading books for pleasure, which, in a development that will alarm many parents, continues to decline as a regular pastime. While four out of five children read books in their own time, only a quarter do so daily and 53% at least once a week.

The report, based on interviews with 1,147 children in 60 schools around England, Scotland and Wales, found television viewing now averages 2.6 hours a day across the age group, though one in 10 say they watch more than four hours daily.

The survey, which has been conducted annually for 14 years, asked for the first time whether children watched television while eating dinner or in bed before going to sleep. It found that 58% watch during their evening meal, while 63% lie in bed watching the screen (rising to almost three-quarters of 13 to 16-year-olds). Two-thirds - particularly the youngest children - watch before school, and 83% turn on the television after returning home.

Rosemary Duff, Childwise research director, said television was now "almost woven into children's lives", but added that the quality of viewing had changed. "A lot of television viewing has lost the 'pay it attention' feel it used to have. It used to be less ubiquitous but much higher in its importance whereas now it is widespread but just part of the background, not just at home but wherever you go."

The Simpsons remains children's favourite programme for the third year running, followed by EastEnders, Hollyoaks and Tracy Beaker, but viewing is fragmented with few "must see" shows.

Anecdotal evidence indicated that children now multitask, keeping one eye on the television as they flick through magazines or use the computer, Duff added. Boys asked by the company to choose between programmes on different channels frequently refused, saying they would "watch both". "They flick from one to another and cannot conceive that they should have to make a decision. They are puzzled that you should put them in a situation of having to make one or anther choice."

Computers are also now a key part of children's private worlds. "The internet is now an essential part of most young people's lives," says the study, with 85% of five to 16-year-olds accessing the net, and over a third (including a quarter of five to six-year-olds) owning a computer or laptop of their own. On average, they go online just over four times a week, spending two hours each time.

The survey shows a rise in internet use, particularly among younger children, driven primarily by a boom in the use of social networking sites, primarily Bebo. Communication, says the report, "has overtaken fun (eg online games) as the main reason to use the internet and study is now far behind".

Almost three quarters (72%) of children have visited a social networking site, and over half have set up their own profile - sometimes lying about their age to sidestep minimum age safeguards. Children as young as eight are now signing up.

Kathy Evans, policy director of the Children's Society, which is conducting its own inquiry into modern childhood, said there was now "mounting public and professional concern about the potential impact of children's TV and internet viewing habits". The inquiry will report next month on children and technology as part of its two-year investigation.