The Advisory Council on the Misuse of Drugs (ACMD) was set up under the Misuse of Drugs Act (MDA) in 1971 on a premise that was thought radical at the time – an independent panel of heavy-weight experts from a range of fields would offer policy advice on drugs not just as a criminal justice issue, but as a social phenomenon too.

Sadly, for most of its existence the ACMD has been used by the government, as one member Dr Les King put it: ‘…as a rubber stamp, a poodle’. That changed with the appointment of Professor David Nutt. He is outspoken, principled, and not easily cowed by authority figures, as well as being a leading specialist with impeccable scientific credentials. That combination proved too much for the home secretary, Alan Johnson, who sacked him for telling an inconvenient truth – government policy is not evidence based.

In fact it is an evidence-free zone. Both internationally and domestically, we see drug supply and availability increasing; use of drugs that cause the most harm increasing; health harms increasing; and massive levels of crime leading to a crisis in our criminal justice systems. Illicit drug profits are enriching criminals, fuelling conflict and undermining security and development in producer and transit countries from Mexico and Guinea Bissau, to Afghanistan and Colombia, with the gravest impacts falling upon the poor and marginalised. Yet particularly at a time of economic stricture, it is crucial that drugs expenditure is cost-effective and humane, which it often manifestly is not.

That is why we have been urging the ACMD to call for a comprehensive review of policy, in the form of an independent and comprehensive impact assessment of the Misuse of Drugs Act. An impact assessment comparing the costs and benefits of current policy with all the alternatives, from stepping up prohibition, through Portuguese-style decriminalisation, to legal regulation would be a process behind which all stakeholders genuinely interested in evidence-based policy could unite, helping break the emotive, polarised deadlock in the debate around drug policy reform. In the longer term, it would ensure greater transparency and trust in the decision-making process, and most importantly help to determine which mix of policies is most likely to deliver the best outcomes.

In the UK, it is now a requirement for all new legislation to have an impact assessment done before it comes before parliament, but this was not the case in 1971 when the MDA was enacted. As we stated during a recent meeting with the prime minister, we believe it is time to correct that anomaly. The UN should also carry out a similar exercise at international level to incorporate impacts on producer and transit countries.

Given this is such an eminently sensible call, why hasn’t it happened already? For the same reason Professor Nutt was sacked – the government doesn’t want the evidence made public because it knows what it would show. As Bob Ainsworth said when we put a similar request to him when he was drugs minister: ‘Why would we do that unless we were going to legalise drugs?’

Accepting the evidence will demand a much more fundamental reform of how drugs policy is handled by the government than tweaking the MDA. Just as with terrorism where security concerns are paramount and there is huge resistance to considering the root causes of radicalisation, the Home Office perceives everything in a criminal justice light. In American psychologist Abraham Maslow’s analogy, when the only tool it has is a hammer, it sees all challenges as nails. Ultimately, we need to de-securitise drugs policy, get the lead on it out of the Home Office, and into the normal kind of cross-departmental framework within which other elements of government social policy operate.