In time-honoured fashion we see the tired trope of cocaine users’ responsibility for violence in Colombia (Colombian president says middle-class cocaine users are hypocrites, 18 June). It is 10 years since the UK and Colombian governments launched their “Shared Responsibility” campaign to highlight links between users and the criminal trade. It was dropped because it was ineffective in reducing demand. This most recent call will have little or no effect on demand, but does serve politicians’ need to distract citizens from the catastrophic failure of the so-called “war on drugs”.

Anyone who buys illegal drugs does contribute to the criminal market. However, this vast unethical trade is co-created by politicians, including President Duque of Colombia, who back a policy of global prohibition. Duque’s predecessor, President Santos, said he would consider legalising cocaine in 2011, and is now a member of the Global Commission on Drug Policy, which collectively supports the legal regulation of drug markets. Unless and until policymakers begin to seriously engage with the issue of who controls the international drug trade, we cannot make progress in reducing opportunities for organised crime and improving international development and security.

Danny Kushlick

Head of external affairs, Transform Drug Policy Foundation

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• This letter was amended on 21 June 2019. An earlier version called the organisation the writer works for “Transform”; this has been amended to give the organisation’s full name.