- Video report by ITV News Correspondent Sejal Karia
The number of children with gambling problems has quadrupled to more than 50,000 in just two years, a study has shown.
Research by the Gambling Commission indicates there could be a further 70,000 children aged 11 to 16 who are at risk of developing problems.
Some 450,000 children bet regularly.
The research suggests more children placed a bet in the past week than drank alcohol, smoked or took drugs.
The findings, reported by the Daily Mail, were described as a "generational scandal" by the Bishop of St Albans, the Right Reverend Alan Smith, a vocal campaigner on the issue.
The watchdog warned that while children were gambling via new technologies, such as apps and online casinos, large numbers are making bets through more conventional means.
Writing in the newspaper, Gambling Commission executive director Tim Miller urged people to "sit up and listen".
He wrote: "While discussions about children gambling might conjure up images of kids sneaking into bookies or sitting alone on their iPad gambling on an online casino, our latest research paints a more complex picture.
"The most common activities that children gamble on are not licensed casinos, bingo providers or bookies.
"Instead we found children preferred to gamble in informal environments, out of sight of regulation - private bets between friends or playing cards with their mates for money."
The study found the most common routes into gambling were fruit machines in pubs or arcades and cash bets with friends, but some admitted using betting shops or online gambling sites, despite them being illegal for under-18s
The commission also raised concerns that close to a million young people had been exposed to gambling through "loot boxes" in video games or on smartphone apps: these can involve a player paying money for an item that is only revealed after purchasing.
The report was based on an Ipsos Mori study of 2,865 11 to 16-year-olds carried out between February and July.
The youngsters were asked nine questions including how often in the last year they thought about gambling, how often they gambled to escape from problems or when they were feeling bad, or if they had ever taken money without permission to gamble.
If they showed four or more of the behaviours, they were classed as a problem gambler.
The results suggested 1.7% of the children were problem gamblers, equivalent to 55,000 youngsters - 42,000 more than in 2016, the newspaper said.
The study also suggested 2.2% of the 11 to 16-year-olds were at risk of developing problems, representing around 70,000 children.
The Right Reverend Alan Smith said: "We need to start taking the dangers of gambling seriously - 55,000 children classed as problem gamblers is a generational scandal."