Thousands of children are being turned into problem gamblers by the easy availability of online betting and slot machines, a report will warn this week.

The study by the charity GamCare finds the rate of problem gambling among adolescents is three times that for adults — 2% of children aged 12 to 15 are classed as addicts, compared with 0.6% of grown-ups.

Some bet so heavily they play truant from school to pursue their habit.

GamCare, which is funded by the gambling industry, is also expected to warn that children who become hooked on gambling are likely to see the problem grow in later life.

The charity says 60,000 children between 12 and 15 in England, Scotland and Wales are compulsive gamblers. It will call for all children to be taught about the risks of excessive betting as part of the school curriculum.

Children from lower income families and “Neet teenagers” (those not in education, employment or training) are more vulnerable than others.

The report is expected to warn that most parents do far too little to stop children gambling because they do not see it being as serious as a drink or drug addiction.

“Gambling is all around us. It is advertised on television, children are accessing internet bingo sites and internet poker sites. They have found ways of lying about their age to access these sites,” said Jane Rigbye, head of education development at GamCare.

“We have found that a huge number of the adult gambling addicts we have helped have been gambling since they were 11.”

Chris Eubank, the former middleweight and super middleweight boxing world champion and an ambassador for GamCare, is to help spearhead a campaign to educate disadvantaged young people about the risks.

Although an estimated 68% of the population gamble in some way, for most it does not become a problem.

However, the proportion gambling every month, including on the national lottery, has risen from 7.2% in 2006 to 10.5% last year. Most teenagers start off using slot machines in arcades or placing bets in betting shops, often with the help of family members.

Some also get on to online bingo and poker sites by lying about their age. According to GamCare, some steal their parents’ credit cards to play.

A spokesman for the Department for Culture, Media and Sport said: “For the overwhelming majority gambling provides good fun and harmless entertainment. A tiny minority may become problem gamblers, however, and it is important their interests are recognised too.

“That’s why we have a strong regulatory regime that prohibits minors taking part in the harder end of the gambling spectrum.”