Ten years ago, I represented Britain at a UN general assembly special session in New York, where political leaders reviewed progress in tackling the illegal drug market, and set out a 10-year plan to eliminate the illicit production and use of drugs such as cannabis, heroin and cocaine. Fast forward to this week in Vienna - where a similar gathering is tasked with reviewing progress and setting out a framework for international drug controls for the decade to come - and the lack of headway is striking.

Albert Einstein defined insanity as doing the same thing over and over again and expecting different results. So far in Vienna, the meeting appears to have been struck by a similar affliction.

Yes, it is every politician's nightmare: a controversial subject that the electorate cares about and that the media write about (some might say) obsessively. But evidence of the failure of policy is overwhelming. All credible studies conclude that there has been no overall reduction in the scale of production or use, and that in many parts of the world the problem has got significantly worse. There are at least 200 million users of controlled drugs. The illegal market generates an estimated $300bn turnover for organised crime. Overall rates of addiction are probably rising, as is transmission of the Aids virus through shared needles. States as diverse as Mexico, Afghanistan and Guinea-Bissau struggle to maintain control as profits from trafficking foment violence and disorder.

Thirty countries still have the death penalty for drug offences and many continue to use it despite clear advice that this breaches the UN charter. The forced eradication of crops in countries such as Colombia condemns whole communities to poverty and ill health. Legal clampdowns increase drug users' marginalisation, and the social and health risks of their behaviour. Perhaps all this "collateral damage" would be justified if the drug market was being reduced. The inconvenient truth is, it is not.

How will the international community respond? Well, the head of the UN drugs agency, Antonio Maria Costa, has issued a report claiming "undeniable success", and governments are on the verge of signing a political declaration that meekly reports: "Some progress has been made." The declaration is essentially a reiteration of the objectives and activities agreed in 1998 - no recognition of a decade's evidence; no new ideas or initiatives. Privately, delegates are acutely aware of the weaknesses and divisions, but have no answers to offer.

Some countries have tried to push for a more honest assessment. Britain is one - we may still be prone to rhetorical posturing and have tied ourselves in legislative knots over cannabis classification, but we do not send lots of people to prison for using drugs. We prioritise treatment for addiction and promote harm reduction approaches to improve the life chances of drug users and to prevent the spread of blood-borne viruses. We also accept that our law enforcement agencies cannot save the country from drugs. This is modern, pragmatic thinking. It will be drowned out in Vienna by a series of exhortations for tougher action in the "war on drugs".

Tomorrow, representatives of all UN member states will adopt a declaration that commits them to another decade of the same strategy, in the hope of achieving different results. Einstein's definition seems to ring true. We're about to witness another walk up the political and diplomatic path of least resistance. It will do nothing to help the millions whose lives are destroyed by drug markets and drug use - and, depressingly, we can all book our seats for 2019, to go through this charade again.

• Mike Trace is the chairman of the International Drug Policy Consortium and the former deputy UK drug tsar

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