London teenagers were carrying knives in the mistaken belief that they offered protection. The Metropolitan Police wanted to communicate that the reverse was true.

After experiencing the consequences of their choices, viewers were invited to ‘Choose a Different Ending’. For the film, and their life.

•4.6 out of 5 average user rating.•2.1% click-through rate on viral video trailers, well above 0.2% industry benchmark for rich media banners.•Net number of views logged would have required a TV budget 600% the size of our spend.•Peer-to-peer debate about the videos and knife crime swelled. At peak, more than 80 comments a day were posted, with a total of over 3,000.•Total views to date, 2,652,012.

•Highest total recall of any Metropolitan Police campaign, ever. 78% among our target.

A series of films was created for Youtube using Annotation Technology,enabling viewers to choose what happened next. Carry a knife? Go to a party? Stab an opponent?

After experiencing the consequences of their choices, viewers were invited to ‘Choose a Different Ending’. For the film, and their life.21 films, ten different endings.