This pedestrian road safety PSA from the U.K.'s Transport for London (TfL) is a modern day retelling of Aesop's "The Tortoise and the Hare" with a suitably stark message for teenagers. The ad shows two groups of teens setting off for a "Hare and Tortoise" party wearing masks. The hares lark around and run as they make their way to the fete, while the tortoises walk sensibly.

The music and gloomy lighting add to our sense of unease as the ad, created by M&C Saatchi, and directed by Rattling Stick's Sara Dunlop, reaches a chilling conclusion, and the masks come off.

The campaign -- running across video-on-demand, cinema, social media and outdoor -- builds on neuro-scientific research that suggests at this age young teens are less likely to exercise restraint.

TfL isn't the first advertiser to turn to one of Aesop's Fables this year -- Mercedes also employed the story for a Super Bowl ad.