Youngsters aged 10 to 14 who watch a lot of movies featuring alcohol are twice as likely to drink, according to new research.
Experts questioned more than 6,500 youngsters four times, asking in each session whether they had seen any of 50 films selected at random.
The teenagers were also asked in each survey if they had ever drunk alcohol behind their parents' back and at what point they started binge-drinking (having five or more drinks in a row).
The films were then analysed for alcohol use, defined as a character's actual or implied consumption or the purchase of alcohol.
The study, published in the journal BMJ Open, found that youngsters had typically seen around 4.5 hours of on-screen alcohol use and many had seen more than eight hours.
It also looked at the impact of parental drinking and children owning merchandise carrying alcohol brands. Some 11% of the teenagers said they owned branded merchandise, such as a T-shirt or hat with the name of a beer on it. Almost one in four (23%) said their parents drank alcohol at least once a week at home, while 29% said they were able to get hold of alcohol at home.
Over the course of the surveys, which were spread over two years, the proportion of teens who started drinking alcohol more than doubled from 11% to 25%, while the proportion who began binge-drinking more than tripled from 4% to 13%.
Parents who drank at home and availability of alcohol in the home were linked with youngsters taking up drinking, but not progression to binge-drinking. Exposure to alcohol in movies, owning branded merchandise, having friends who drank and rebelliousness were associated with both.
The results showed that children who watched the most films featuring alcohol were just over twice as likely to have drunk alcohol and 63% more likely to have made the transition to binge-drinking than those who watched few such films.
A spokesman for the Department of Culture, Media and Sport said: "Alcohol in films is an issue that is covered in the classification guidelines used by the British Board of Film Classification, and the promotion or glamorisation of drinking is something that is taken into account in classification decisions."