AMERICAN companies behind some of the most popular video game titles have come under attack from the industry watchdog amid fears that “hidden” sex scenes are lurking within their products.

The Entertainment Software Rating Board (ESRB), the American industry body, has instructed all the main games publishers, which include companies such as Electronic Arts and Activision, to examine their games to ensure that they do not contain any inappropriate, sexual content. If they fail to comply, they face hefty fines and could see their games pulled from the shelves — potentially leading to millions of dollars in lost sales.

The crackdown, revealed in a leaked private e-mail sent by the ESRB, follows a scandal earlier this year in which Grand Theft Auto: San Andreas — one of the cult series which has sold millions of copies worldwide — was pulled from sale, when it emerged that hidden sex scenes embedded in the game could be “unlocked” using a patch downloaded from the internet. The patch, known as Hot Coffee, allowed players to follow the game’s hero into his girlfriend ’s room and command him to have sex with her. Previously the hero, CJ, had always been invited to a girlfriend’s house for coffee if he was successful, but the camera stayed outside.

The game was re-rated as appropriate for adults only, restricting its potential audience.

Retail chains such as Wal-Mart removed it from sale — a move which its maker, Take-Two Interactive Software, a Nasdaq-listed company, said would cost it about $45 million (£25 million) in lost revenues.

Video game publishers often leave hidden content on their games — sometimes deliberately as a bonus or so-called “Easter egg” — for the most tech-savvy players.

But game publishers are legally bound by the ESRB to disclose any significant content when submitting a game for rating. If material is found not to have been disclosed that could have had an impact on the rating, the ESRB can take corrective action ranging from monetary fines to pulling advertising or recalling the product.

In the e-mail the ESRB demands that publishers re-examine all titles published since September 1, 2004, to ensure that they do not contain “pertinent” content — “even if [the content] is not intended to ever be accessed during game play”.

If hidden sex scenes are found the publishers must notify the ESRB by January 9 so the board can re-rate the title if necessary.

The e-mail adds: “If you fail to notify us of previously undisclosed . . . pertinent content and such content becomes playable . . . punitive in addition to corrective actions may result”.

Though the games rating system is voluntary, virtually all games that are sold in retail outlets are rated by the ESRB which is also responsible for the enforcement of its rating system. Nick Parker, analyst at Screen Digest, said: “Most of the games in production and about to be launched from the main games publishers will not contain gratuitous sordid content because they understand their market.”

Times Recommends

• Lies and cover-up at MG Rover exposed by report
• High oil prices push manufacturing costs up
• Primark founder steps down as chief executive