The government’s decision to reject the advice of the Advisory Council on the Misuse of Drugs (ACMD) that Ecstasy should be reclassified as a Class B drug was predictable but regrettable. Following the decision to reject the advice on keeping cannabis at Class C (the drug was reclassified back to Class B in January), some commentators have questioned the ACMD’s role and asked whether it has a future. The government’s refusal to follow robust independent scientific advice does raise important questions about the classification system and the evidence base for drug policy.

Although ACMD recommendations on classification make the headlines, its role is much broader: to give advice on “measures which ought to be taken for preventing the misuse of such drugs or dealing with social problems connected with their misuse”. The terms of reference only briefly mention ‘alteration of the law’, and it has done groundbreaking work on parental drug misuse and substance misuse among young people. All but one of its 2008 recommendations on cannabis – the one on classification – were accepted.

The council is not without critics. Some claim it is filled with covert drug liberalisers or legalisers, but its membership is arguably unrivalled internationally in its scientific and medical expertise, and includes representatives of drug treatment, criminal justice, education and prevention. The council has also striven to address criticism from the Commons’ science and technology committee. Some of its meetings are now held in public, and the suggestion that we had failed to keep the classification of different drugs under review led to both the Ecstasy review and a commitment to carry out a ‘systematic review’ of other classified drugs.

The committee also aimed its fire at the Misuse of Drugs Act 1971, concluding that there was no convincing evidence that it has had a deterrent effect, and describing the classification system as “not fit for purpose”. It called for the current system, “ultimately a political decision”, to be replaced by a more scientifically based scale of harm, and for penalties for possession and supply to be determined not by classification but by factors such as levels of associated criminal activity. The government declined to follow its advice.

It has been largely forgotten that in January 2006 home secretary Charles Clarke promised MPs a review of the classification system. He was concerned about the limitations of the system, with decisions on classification often addressing “different or conflicting purposes” and sending “strong but confusing signals” about the consequences of using a particular drug. Following the perfect storm that hit the Home Office and led to Clarke’s replacement by John Reid, the commitment to review the classification system was quietly abandoned.

The ACMD has an important role to play in informing drug policy and supporting the delivery of the drug strategy. For all the heat generated by the collision between science and politics, it is unlikely that this or a future government will wish to see its demise. But what of the drug classification system? The decisions on Ecstasy and cannabis are evidence that we appear to have reached a situation where, for political reasons, drugs can only be placed within, or moved up, the classification system, but cannot be moved down, regardless of the evidence. Decisions on the penalties for the use and supply of controlled drugs should be based on the best available information, otherwise the drug laws themselves lose credibility – especially among young people. The government is very unlikely to want to open a Pandora’s box by reviewing the system, but what if there is a change of government?

When the Conservative Party leader David Cameron was a member of the home affairs select committee in 2001, he supported the downgrading of cannabis and Ecstasy. He has since changed his view on cannabis because the drug “is so much more powerful than it used to be”. However, in the book Cameron on Cameron he is on record as supporting a review of the ABC drug classification system: “I think the whole classification system is in need of a major overhaul because it seems to me that the ABC method doesn’t really get it right.” There are both punitive and progressive strands within Conservative drug policy but, just as ‘only Nixon could go to China’, a Conservative government may adopt an unexpectedly progressive approach. A review of the Misuse of Drugs Act, though unlikely, may not be impossible.

Martin Barnes is chief executive of DrugScope, the national membership body, and a member of the Advisory Council on the Misuse of Drug