A new video game that gives players the option to kill civilians in a terrorist attack is poised to become the single most lucrative release in the history of entertainment when it goes on sale on Tuesday.

Call of Duty: Modern Warfare 2 is the latest in a series of ultra-realistic first-person war games, the last of which won a Bafta earlier this year for its story and character development. In the course of the ten hours or so the game will take to complete in solo mode, the player will assume a variety of roles in a global war against Russian ultranationalists led by Vladimir Makarov.

Like many war-themed titles, the game – set five years in the future - features bloody conflict throughout, but Modern Warfare 2 is so harrowingly realistic at some points that an on-screen warning offers players the option to skip scenes they may find disturbing.

One of the most controversial of these is an episode where your character must choose whether to kill unarmed civilians in a Russian airport in order to infiltrate a terrorist sect successfully. The scene is so genuinely shocking in its brutality that the game’s distributor Activision has already attempted to forestall criticism by issuing the following statement.

"The scene establishes the depth of evil and the cold-bloodedness of a rogue Russian villain and his unit. By establishing that evil, it adds to the urgency of the player's mission to stop them.

"Modern Warfare 2 is a fantasy action game designed for intense, realistic game play that mirrors real life conflicts, much like epic, action movies. It is appropriately rated 18 for violent scenes, which means it is intended for those who are 18 and older."

Critics of the game, though, accuse Activision of being disingenuous. Warnings of extreme content, they say, are like a red rag to a bull, and have a particularly strong appeal to younger players who are more likely to be affected by the action they see onscreen.

Keith Vaz, MP, a long-time critic of violence in video games, told The Times: “I am absolutely shocked by the level of violence in this game and am particularly concerned about how realistic the game itself looks.

“Whilst I appreciate that this game has been certified as an 18, I firmly believe that certain levels of violence should not be made into interactive entertainment. This would include acting as a terrorist, as is the case here, or violence against women. I will be raising this issue in Parliament on Monday.”

The last game to generate similar controversy was Grand Theft Auto IV, released in April, 2008, in which players steal cars and murder their way to the top of the big-city underworld.

On release, GTA IV broke all records for an entertainment product, grossing $300 million in its first 24 hours on sale, nearly three times as much as the movie blockbuster Iron Man, which was released the following month.

Retailers in the UK claim that Modern Warfare 2 is already on target to break this record, despite Activision having added £10 to the standard retail price for similar games. The high-street specialist chain GAME is opening 320 of its stores on midnight on Monday to cope with expected demand.

Stuart Rowe, Chief Operating Officer of the online retailer, Play.com, told The Times: "Modern Warfare 2 will undoubtedly become the most popular video game of all time. The demand has been unprecedented, pre-sales of the game have already overtaken all previous records set across our broad range of product categories."

On Monday evening, Amazon confirmed that Modern Warfare 2 will be its biggest selling video game yet, with advance orders running 50 per cent higher than for GTA IV.