Police say parents have complained their children are taking to stealing money, DVDs and computer games to pay off the debts they have incurred from playing a game called 'pits', where they flick marbles into an open water meter cover on the street.
Some children playing it are as young as five.
PCSO Dan Amador, of Devon and Cornwall Police, said young children have started playing the traditional game for hard cash, and then are unable to pay off their debts:
"Historically this game would involve winning each other's marbles - but it has come to our attention more and more children are playing each other for money.
"Over recent weeks we have been approached by parents telling us that their kids are asking for money to pay back debts owed to other children.
"I have also heard that money has been taken out of purses and things around the house have gone missing, like DVDs and PlayStation games."
Police are now trying to talk to parents about the problem, going door-to-door to discuss it and offer advice.
Are you surprised by this?
Whatever happened to playing for fun?!