Sir,

To label America’s ongoing efforts to legalise cannabis an ‘abject failure’ is both uncharitable and unimaginative (‘Joint failure’, 15 October).

Attempts to undo 50 years of the most rigorously enforced prohibition ever attempted in the modern world will of course take time. 

The legal market is competing against the purest free market in the world which, naturally, is proving to be rather resilient. No policy has ever been implemented perfectly at the first attempt. 

Nevertheless, a number of desirable outcomes have been achieved in regulated markets: lower levels of youth usage, decreased levels of the riskiest drug use, diversification of available product, taking money and power out of the hands of criminal gangs and a focus on reducing the harms associated with cannabis use.

Clearly there is still work to be done. Lowering the taxes levied on cannabis is a start, but we cannot allow ourselves to fall into the trap of letting the perfect be the enemy of the good. Let us not forget that the alternative to legally regulated markets is prohibition, for which the label ‘abject failure’ would be far too kind. It’s high time the UK went down the same path. 

Thanks to the trial-and-error approach of countries such as the US, we’ll be in an even better position to do so.