When I read the comments of the mayor of London Sadiq Khan that the people of the middle class cocaine, fueling violence in the capital last week, I went to Medellin, to Colombia. On Tuesday, Cressida Dick, the Metropolitan police commissioner, followed up, calling liberal cocaine users hypocrites. Reading about this debate in a notorious cartel city, I agreed largely with Khan and Dick. But I couldn’t help but think about how much further than London the consequences reach.

As a journalist I’ve covered issues to do with youth violence in our capital, and I have also found myself around the middle classes of which Khan speaks. The links are blindingly obvious. In areas of west London, for example, where extreme wealth is juxtaposed with tower blocks and estates, it’s not surprising to see how some young people from poorer communities are seduced by the lifestyles they can see within reach.

Violent crime in the UK rose in the past year, and the contributing factors are far more complex than simply the demand for cocaine and other drugs from the middle classes. However, estimates suggest that 875,000 people used cocaine in Britain in 2017-18, the highest number in a decade. If a gram costs up to £100, it’s safe to assume that many coke users have cash to burn.

Five years ago I arrived in Colombia to work as a teacher in a university, but also spent time working in networks engaging with sex workers and families who had lost loved ones in the violence between guerrillas, paramilitaries and narcos.

Despite the stereotypes about Colombia, cocaine was nowhere near as prevalent as people may think. There was one occasion at a football match where a guy in front of me pulled out a little knife to do a bump of coke, and I saw a few people taking the drug at a few nightclubs. But on the whole the only times I really saw it were on the rare occasions I mixed with westerners.

I remember going for drinks with some British graduates who were working in , a notoriously violent Medellín neighbourhood. We had a conversation about the legacy of , and one of the women expressed her distress at the damage that it had caused for the younger generations. She aspired to work in development and seemed pretty right-on. Half an hour later she was snorting coke in the corner of the bar. It was an attitude I grew familiar with among some researchers and tourists visiting Colombia.

There’s a wilful disconnect that people seem to be able to make between their actions and the bigger picture, and it’s pretty inexcusable coming from well-off, well-educated westerners who can’t really claim ignorance. I witnessed first-hand the effects of the drug war in Colombia, the legacy of corruption that the cocaine market financed, and the severe impact that it has had on the lives of people who want nothing to do with it. When I see people I know casually contributing to that I find it infuriating. But when I have raised my concerns, just about everyone I have spoken to dismisses the connection.

Drug violence was blamed for Mexico’s record of more than 29,000 murders in 2017. Civilians are caught in the crossfire in the war on drugs, and the demand is fuelled by white, middle-class drug users in North America and Europe.

Some would argue that the war on drugs is failing and that legalisation would take the power away from the criminals. I’m inclined to agree, but this looks unlikely to happen soon.

Colombia’s new president, the rightwing Iván Duque, will be inaugurated next week. His plans include an aggressive crackdown on coca cultivation in the country, a proposal that was extremely popular with his supporters.

It’s clear that western cocaine users have to accept they are contributing to violent crime that has left hundreds of thousands dead in Latin America over the past decades, and is spilling on to British streets.

Perhaps the carnage in Latin America is a comfortable distance away from those snorting coke at weekend parties across the UK. If your money funds the market, you are complicit in the consequences.