Behold the power of Sian BerryWatch
The green candidate for mayor of London has pledged to end all murders in London within ten years. Her other policies include making piers Morgan likeable as well as powering all of London using wind chimes and hemp.
Presumably when a murder is about to happen she will spontaneously appear and say firmly 'No!' stunning the assailant and causing them to change their ways and become vegan.