The Call of Duty: Modern Warfare 3 'Rank Up XP' promotion spotted by Forbes will put codes on bottles of Mountain Dew and packets of Doritos crisps that give players double XP time in-game.

So when you take a headshot from a high level sniper rifle, you won't be able to tell if they've played more of the game guzzled a truckload of potato chips. Perhaps the guy heading a server with every unlock is quite good at Call of Duty, or he's just consumed more litres of luminous energy drink than you.

There's apparently no limit to the lengths marketers are prepared to go to shift a big new game, but cheapening your entire unlock and experience system for the sake of a drinks promotion crosses a line we didn't even know existed.

Where will this end? They should rename the series Call of Dewty and replace all of the grenades with exploding cans of soft drink. Claymores can be packets of Doritos that explode when enemies approach, shredding them with a cloud of tasty nacho shrapnel. Then they'll see a kill cam replay of their maizy death, sponsored by Pepsi, of course.