High street shops in Harrow have been caught out selling violent video games to an underage girl in an undercover investigation.
Woolworths, Game and Maplin, in Harrow town centre, all sold 18-rated games to the 15-year-old, who was working for Harrow Council Trading Standards and Which? Computing.
All three shops have now launched internal investigations into the sales and will face legal action from the council if caught out again.
Woolworths sold Grand Theft Auto (GTA) - Vice City Stories, which shows scenes of sex and violence, and specialist shop Game sold Condemned 2, which is subtitled "a terrifying descent into chaos", to the girl without question.
In the Maplin store, the assistant asked the investigator's age, but did not refuse the sale of Hitman, even when she said she was 15.
Ash Shah, assistant head of Harrow Council trading standards, said: "Staff should realise that they have a moral and legal duty to stop these sales from taking place.
"There is a mixed but growing body of evidence that very violent games like this can sometimes influence under-age players with reports of anti social behaviour linked to them, in extreme cases even fatalities."
The six other Harrow stores that were tested in the operation in May - Tesco, Argos, Debenhams, HMV, Currys Digital and Entertainment Exchange - all refused to sell the game to the teenager.
Computer games are classified with age restrictions, like films, by the British Board of Film Classification (BBFC). It is an offence to sell video games to people who have not reached the age specified on the product. The maximum penalty is £5000 and a six month jail sentence.