A study by the schools health education unit at Exeter University estimates 759,000 youngsters aged 11 to 15 are in work. One in 25 14-year-olds works more than 10 hours a week.
It is illegal for children to work under the age of 13 unless they are working for a parent or guardian.
The research was published yesterday to raise awareness before the second reading of a private member's Bill on Friday urging tighter controls on employment of children.
The Employment of Children Bill was drawn up by Chris Pond, Labour MP for Gravesham, in Kent. The report said "earners" were also more likely to have a boyfriend or girlfriend, drink alcohol and to have been offered drugs.
John Balding, director of the unit, said: ``It seems participation in the world of work, as well as raising health and safety issues, is also connected with initiation into a variety of other health-related activities."
A spokeswoman for the National Union of Teachers said: ``There is a potential danger that children working too many hours could damage their future for the sake of earning pounds 10 a week." She added that parents should make sure children balanced work and homework and that shopkeepers should not sell drink and cigarettes to children.
The boys mainly had paper or milk rounds, followed in popularity by a range of other jobs including manual work, baby-sitting, farm work or gardening, paid housework and working in shops. The most popular jobs for girls were baby-sitting, paid housework, and a paper or milk round.Reuse content