Facebook has removed one of its applications after provoking public outrage.
The "Superpoke" application on Facebook, called Shank, lets Facebookers "virtually knife" each other.
Shank could be added by any Facebook member and appeared in the user's profile as a small knife with a black blade.
Once installed as part of the Superpoke application from third party developer Slide, the application allowed users to "shank" (a "street" term for stab) their friends.
It has been attacked by anti-knife crime campaigners who accused Facebook of being irresponsible in light of the numbers of teenagers who have become victims of knife crimes - especially in the capital.
"The stupidity of having this on their site is unbelievable", said John Knox, whose nephew, the Harry Potter actor Rob Knox, was stabbed in London.
He added in the interview with The Times: "And they deliberately use the street term 'shanked', which is even worse. They are targeting the kids who are on street corners carrying knives".
Raymond Stevenson, a spokesman for the London-based anti knife crime campaign Urban Conceps told The Sun that the application was "appalling".
Facebook says it has now removed the application and added in its statement: "Facebook does not condone violence whatsoever. Slide, the makers of the SuperPoke! application, have now removed this particular action".
A spokeswoman for Slide said: "Slide does not condone violence whatsoever. We removed this particular action last week because it misrepresented the SuperPoke! brand".