The 40-second ad spot has been refused permission to air on television by regulator Clearcast, which deemed the images too brutal for young audiences. It will be shown via YouTube and in cinemas before films rated 12A and above.
The disturbing visual is designed to show how victims feel silenced by bullies and drive awareness of the devastating effects bullying can have.
The campaign hopes to promote its CyberMentors service, a social networking site where children and teenagers can access support and advice from each other.
Created by M&C Saatchi, images from the ad will also appear in an outdoor campaign with the strap line “You can speak out now”.
The campaign is in memory of bullied school girl Megan Gillan, whose life was cut short in January last year after being bullied online and at school.