The account holder must give express permission for charges, and the industry needs "to do more to protect children and treat its customers fairly."
Any hidden costs of an app must be declared upfront, rules the OFT, and that any form of in-game advertising must also be declared, as must any use of personal data.
The OFT also advises parents to ensure passwords are in place for every purchase where applicable and to keep watch over what apps their children are engaging. "The online and apps-based games industry has already made significant improvements during our consultation process," said OFT chief exec Clive Maxwell. "But it still needs to do more to protect children and treat its customers fairly."
An example of a title unlikely to comply with the OFT's Principles:
"A game is advertised at a specified price without further qualification. However, on creating an account or downloading the game, the consumer may not access a significant portion of the game’s content, or continue to play, without making a further payment or series of payments."
UKIE stated: "Done responsibly, micro-transaction based business models give choice and value for both players and businesses. Flexibility for companies to operate different business models is crucial, and it is good to see the OFT recognise this. We will work with the OFT on briefing sessions for games companies to better understand the application of the principles." The Principles for online and app-based games are available to read .
Creators of these online and app-based games have two months to adhere to the Principles, or face action.