Retailers who sell age-rated video games to under-age children will face prison sentences, as part of new EU regulations, about to become UK law.
The Video Standards Council will now apply ratings to games in the UK, following specifications set out by the pan-European Pegi authority.
The VSC will also be in charge of ensuring shops stick to the new regulations, with criminal sanctions now available.
Previously the ratings system had been operated by the British Board of Film Control, who will still be consulted over particularly violent games, or those featuring sexual content.
The government says the change, which comes into effect in July, will make regulation "simpler and stronger" and give parents peace of mind.
Creative Industries Minister Ed Vaizey says: "It will give parents greater confidence that their children can only get suitable games while we are creating a simpler system for industry having their games age-rated."
The sanctions, which don't apply to games bought online, will help get the message home to retailers that under-age sales can't be tolerated, according to Richard Wilson of games industry body Tiga.
"The fact there are criminal sanctions in place will mean that retailers will want to train and support their staff," he said.