The game, which depicts graphic scenes of violence and allows players to engage the services of prostitutes, has been promoted at the Leeds branch of Smyths toy shop with in-store adverts and a midnight opening on the day of the game’s release.
The store, which caters mainly to young children, has been criticised by leading academics studying the effects of videogame violence.
Dr Nicolas Robinson, Associate Professor in Politics and Videogames Research at the University of Leeds, said: “You do have to be 18 to buy this game – I could be in that shop with my kid and easily want to buy Grand Theft Auto for myself as an adult.
“But do these games end up in the hands of kids who shouldn’t be playing them? The answer to that is absolutely yes.
“The real problem is peer pressure – kids will be talking about these games in the playground, watching adverts on TV and seeing clips on YouTube.
“Kids should be protected from certain content. I believe Grand Theft Auto is a very sophisticated satirical piece of work – and I actually think that most kids under 18 just won’t get the satire.
“And if you don’t get the satire, it’s actually much more problematic than if you can,” he added.
“As a culture, we have a certain view about alcohol – parents know that giving a child neat whiskey is not a good thing – we don’t feel that way about games.”
Prof Brad Bushman of Ohio State University, is one of the leading researchers in to videogame violence. He said: “It is a really bad idea to market 18 rated games to underage children.
“Our studies show that violent videogames increase aggressive thoughts, angry feelings, physiological arousal (e.g., heart rate, blood pressure), and aggressive behaviour.
“Violent games also decrease helping behaviour and feelings of empathy for others.
“ The effects occurred for males and females of all ages, regardless of what country they lived in,” he added.
Robert Guckian, a spokesperson for Smyths, said: “As a leading entertainment provider, Smyths Toys Superstores cater for all ages.
“Grand Theft Auto V has a PEGI rating of 18+ and will not be sold to anyone under this age. ID is required for anyone wishing to purchase this game who may look under this age.”