Up to two-thirds of children in Britain are not getting enough sleep and have missed out on as many as 4,500 hours by their seventh birthday, according to research published today.

The findings reveal a dramatic shift in nightly routines, with one in 10 of the 500 parents surveyed admitting they had never read their children a bedtime story.

Instead, children are now falling asleep to television shows, computer games and videos.

One in eight children actually sleeps less than the amount recommended for adults, with that figure rising to 25% for children whose parents are out at work.

And although most parents agreed that lack of sleep impaired their children's performance and behaviour, two-thirds were not even aware of how much sleep their children should be getting.

Jim Horne of Loughborough University, an expert in sleep deprivation, said: "Bedrooms are changing from places of rest and tranquillity to places where there are lots of things to keep children awake, such as computers and televisions.

"I would not allow a child to have a television or a computer in their bedroom, or at least place firm limits on their use. Evidence suggests that adequate night-time sleep is just as important as healthy eating and regular exercise for children to develop.

It is believed that sleep deprivation may harm neurological development and can contribute to school-related problems, including attention deficit hyperactivity disorder.

Some experts believe chronically tired children will become chronically tired adults, unable to cope with the stresses of modern day life.

Press Association