Middle-class parents who introduce their children to alcohol with a glass of wine at family dinners will not protect them from becoming problem drinkers, campaigners have warned, with a new study showing affluent teens were twice as likely to drink regularly than those from poorer backgrounds.

About 70% of 15-year-olds from the least deprived backgrounds had tried alcohol, compared with approximately half from the most deprived, according to a study of 120,000 teens published by the Health and Social Care Information Centre.

Just over three in five young people reported they had previously had a whole alcoholic drink, defined by the survey as ”not just a sip”, with the richest 15-year-olds twice as likely to be regular drinkers.

White teenagers were far more likely to have had an alcoholic drink than those from a black and minority ethnic background, as more than 70% from a white background had drunk alcohol compared with just over a quarter of BME teens, though religion is likely to be a major factor in that statistic.

Teenagers from well-off families are also more likely to continue drinking after first trying alcohol, according to the study, which is backed by the Department of Health.

Young people in the south-west were the most likely to have had an alcoholic drink at 72%, compared with 41% in London, the region with the lowest proportion. Barnsley in South Yorkshire had the highest proportion of teenagers who had drunk alcohol, at 77%, followed by Devon and Cornwall.

It is not illegal for a child aged between five and 16 to drink alcohol at home or for someone over 18 to buy a 16-year-old beer, wine or cider if they are eating a meal together at a table in licensed premises.

Dr Sarah Jarvis, medical adviser to the alcohol education charity, Drinkaware, said parents should not underestimate the potential damage alcohol could do to young teens, even in small quantities. “Alcohol can harm young people while they are still developing, which is why the UK chief medical officers say an alcohol-free childhood is the best option,” she said.

“Young people’s brains are still developing, and they may be more vulnerable to long-term effects on brain and educational achievement than adults even if they drink within government-recommended upper limits for adults.”

Brain and liver damage, an increased risk of accident and injury or involvement in violent or dangerous situations were just some of the risks of teens starting to drink earlier, Jarvis said, as well as the effect drinking can have on schoolwork.

Rather than choosing to give children alcohol in controlled circumstances to “de-mystify” drinking, Jarvis said parents should have frank conversations with children about the risks. “As a parent, you have more influence than you might think. Your child is likely to come to you first for information and advice about alcohol, and you can help shape their attitudes and behaviour towards alcohol by being a role model for responsible drinking,” she said.

Nick Sheron, a liver specialist at Southampton University, told the Times that French drinking culture, where children are introduced to watered-down wine at a young age at family gatherings, was inherently different to British.

“The idea you can ‘inoculate’ children by introducing them early tends to be one promoted by the drinks industry, but all the data works the other way,” he said.