Britain's most senior police officer has hit out at middle class cocaine users who worry about issues like the environment and fair trade but believe there's "no harm" in taking the class A drug.
Gangs that deal drugs are linked to violent street crime, but Metropolitan Police Commissioner Cressida Dick said demand for illegal substances remains high, and has gone up recently for cocaine.
The senior officer joins a number of public figures including London mayor Sadiq Khan and justice minister David Gauke to criticise middle class drug takers.
Ms Dick recalled meeting a young girl who said she was afraid when she saw objects used for drug-taking in the stairwell near her home.
She went on: "There is this challenge that there are groups of middle class people who will sit round happily thinking about global warming and fair trade and environmental protection and all sorts of things, organic food, but think there's no harm in taking a bit of cocaine. Well there is. There is misery throughout the supply chain."
Violent crime has risen nationally in the past few years, and so far in London this year Met figures show there have been 87 homicides, with the rise partly fuelled by street violence.
The detection rate is around 80% compared with 68.5% last year, the commissioner said, with suspects charged in 74 cases, and 123 arrests made.
Although levels of violent crime appear to be stabilising, as they have done over the summer in previous years, the number of murders so far this year is still heading to be higher than last year, when there were 131 deaths including 13 in terrorist attacks.
Officers have seized 1,200 knives and 140 guns since April, and the use of stop-and-search powers has risen.
Detective Superintendent Sean Yates from the Met's violent crime taskforce said one part of solving street violence would be for teachers to help warn primary school children away from knife crime.
"There should be conversations had in schools, not necessarily by police officers but by teachers with their children. The teacher understands the class dynamic," he said.
"We've seen an explosion in social media, all young children now have got phones. It's not unknown for seven or eight-year-old children to have phones. They are being exposed to violent incidents intentionally or not because they're viewing this on social media.
"The teacher knows the classrooms better than any police officer would, and they can have those conversations one-to-one with children about what they might be being exposed to, what they're witnessing, or if they're peripherally being drawn into it."