Well-educated parents of white children were most likely to allow their youngsters to have a tipple than those who were jobless or had lower qualifications.

And heavy drinkers were no more likely to let their children take alcohol than light or moderate drinkers.

Parents who abstained from alcohol tended not to allow their children to drink.

As Christmas approaches and many children will be allowed a glass of wine with their festive meal, scientist warned there was no evidence supervising children's drinking protects them against harmful drinking as they grow up.

The study by University College London and Pennsylvania State University warned previous research showed those who start drinking early are more likely to fail at school, have behaviour issues, as well as alcohol and substance problems in adulthood.

The results were based on new findings from the Millennium Cohort Study involving 19,517 children born in the UK at the turn of the new century.

Lead author Professor Jennifer Maggs from the Centre for Longitudinal Studies at the UCL Institute of Education said: "Parents of socially advantaged children may believe that allowing children to drink will teach them responsible use or may in fact inoculate them against dangerous drinking.

"However, there is little research to support these ideas."

The study looked at parents' drinking habits and attitudes to drinking, linking these to information on family structure, employment status and parents' educational attainment.

When the child turned 14, their parents were asked "Do you allow your child to drink alcohol?"

No further questions were asked about the timing, context, or reasons underlying drinking, for example whether it was supervised by parents or other adults, how much alcohol was allowed to be consumed, or whether parents allowed their children to drink with their peer.

Overall 17-per cent of parents allowed their child to drink.

Parents of white children who were employed, had more educational qualifications, and who drank alcohol themselves, were more likely to allow their adolescent children to drink than unemployed parents, those with fewer educational qualifications, and ethnic minority parents.

By age 14, almost half the children said they had tried more than a few sips of alcohol.

Three years earlier only about 14 per cent had done so.

Katherine Brown, Chief Executive of the Institute of Alcohol Studies, said: "The Chief Medical Officer recommends that an alcohol-free childhood is best, with children not drinking any alcohol before the age of 15. 

"This is important guidance because alcohol can harm children given their bodies and brains are not yet fully developed.

"It is worrying to see that this advice may not be getting across to parents, who are trying to do their best to teach their children about alcohol. 

"We need to see better guidance offered to parents via social marketing campaigns and advice from doctors and schools. 

"Parents deserve to know they can have a positive impact, and can reduce health harms associated with young people drinking."

The study was published in the Journal of Adolescent Health.