Grand Theft Auto IV is due for worldwide release on 29 April, bringing to an end months of legal and regulatory wrangling.

Take-Two's controversial game has faced opposition from the mayor of New York owing to its environmental likeness to the Big Apple, while US attorney Jack Thompson has been vehemently opposed to the release since it was announced.

Thompson threatened to sue Take-Two in September 2007 in an attempt to prevent the release of GTA 4 after claiming that one of the characters in the game satirises him.

Last week Thompson made a last ditch attempt to stop the game by sending an open "letter of shame" to Mrs Zelnick, the mother of Take-Two chairman Strauss Zelnick.

Despite these problems, the fourth instalment in the popular series is expected to be a huge success, with worldwide sales predicted to hit six million copies in the first week.

The Entertainment Software Rating Board (ESRB) has given the game an 'M' rating, meaning that it is suitable only for gamers over the age of 17.

The organisation has issued a warning to parents to make sure that they are aware of the game's violent scenes.

"According to the Federal Trade Commission, a parent is involved in the purchase of a video game nearly nine out of every 10 times," said the ESRB in an official statement.

"So it is critical that parents consider the assigned rating carefully when purchasing or renting computer and video games for their children."