A poll of youngsters involved in a national youth programme found 42% started drinking before they were 13, with 29% saying they drink to get drunk.

The national poll questioned 1,250 10 to 19-year-olds involved in the Government-funded Positive Futures programme, which offers sport and vocational programmes to disadvantaged young people.

Half (50%) said they had been involved in fighting or aggressive behaviour as a result of drinking, and a quarter (24%) had been in trouble with the police. Other effects differed in relation to gender, with one in three young females admitting to greater sexual irresponsibility and young males reporting higher levels of vandalism.

One fifth (18%) had experienced memory loss and the same amount had taken another drug while drinking. Half claimed their parents condoned or did not care about their drinking, and 42% knew family and friends with alcohol-related problems.

Just over half (52%) bought alcohol from a local corner shop, off licence or supermarket, and up to 44% drank it in their park, street or elsewhere in their housing area. But the poll also found 46% thought sports and other positive activities would reduce alcohol-related crime and anti-social behaviour.

Clare Checksfield, the chief executive of Crime Concern, which manages the Positive Futures programme, said: "When young people are drinking young, then prevention work has to start early too. Now is the time to act.

"We need to tackle a wider drinking culture and together make certain that parents and peer groups are involved. Young people are taking risks with their health and with their future by getting involved in alcohol-related violence."

She added: "We need to build on the Positive Futures model of developing strong relationships with young people based on trust, and try to reach out to as many young people as possible."

Vernon Coaker, Parliamentary Under-Secretary of State for Crime Reduction, said: "Alongside tough, systematic enforcement of the law we are working with local authorities and schools to educate young people about alcohol harm at an early stage. A major research programme currently under way will develop this work further and identify what makes the biggest impact on the young. This research will help to shape the future direction of drug and alcohol education across the country."