The Mayor of London tweeted a threat to arrest anyone carrying a knife in London at 10:02 London time. The Tweet also contained a link to his plan to his plan to combat the growing crime in the city.
No excuses: there is never a reason to carry a knife. Anyone who does will be caught, and they will feel the full force of the law. https://t.co/XILUvIFLOW
— Mayor of London (@MayorofLondon) April 8, 2018
Statistics for the first quarter of 2018 show "London['s] murder rate overtakes New York's" and as this BBC article states the violence is attributed that to knife crime.