Children have become "screen kids" with many of them having televisions or computers in their bedrooms, a report says.
Youngsters from poorer areas spend "substantially" more time in front of TVs and than those in affluent areas, the National Consumer Council (NCC) found.
Nearly half the affluent children surveyed for its report had televisions in their bedrooms. This compared to 97% of the nine to 13-year-olds surveyed from deprived areas.
Children from poorer areas were six times more likely to watch TV during the weekly evening meal.
And around a quarter of youngsters in this group had the television on at lunchtime on Sundays compared to one in 30 children in better-off neighbourhoods.
The NCC's Watching, Wanting and Wellbeing report links increased TV viewing hours with greater exposure to marketing and higher levels of materialism.
NCC chief executive Ed Mayo said: "Today's children are now 'screen kids'. In some streets, every bedroom has a television for children and many have a computer."
He said TV and computer screens could be turning into the "electronic babysitter".
Children in more deprived areas were most likely to watch commercial television and TV shows made for an older audience. Youngsters in disadvantaged areas also had greater levels of unsupervised access to television and the internet.
The NCC report was based on questionnaires completed by 557 nine to 13-year-olds across six schools - two primary schools and one secondary in areas ranked in the most affluent 15% and two primaries and one secondary in areas ranked in the most deprived 15%.
