A survey by Norwich Union Healthcare shows that only one in eight children takes the ideal of one hour of exercise a day, although most say they enjoy sport at school.

One in five does just one to two hours exercise a week and 12% do no exercise outside school.

Parents

Although 77% of parents questioned said they thought physical activity was as important as school work and 98% considered it vital for health, most admitted they never did any sport with their children.

Half thought schools should be responsible for encouraging children to keep fit and two out of three thought children were less fit now than in their youth.

Computers use up much of children's time

Children's health expert Professor Neil Armstrong, of Exeter University, blamed the growing use of computers, pressure on the school curriculum from other subjects and demands on parents' time for the statistics.

Norwich Union Healthcare is launching a campaign to get children fit, headed by Leslie Ash, who plays Debs in BBC sitcom, Men Behaving Badly.

She said: "It's crucial to promote physical activity during a child's formative years - the future health and well-being of our children depends on it."