The sources of evidence[1] that the ACMD uses are In order to have a rough but quantitative measure of the harms of a drug, the ACMD uses[1] a risk assessment matrix, where nine different aspects of harm for each drug are evaluated: In 2006, the Science and Technology Select Committee of the UK House of Commons conducted a series of case studies examining the government's handling of scientific advice, risk and evidence in policy making.

Although the Council has produced useful reports explaining the rationale behind its recommendations on drug classification decisions, we found a lack of transparency in other areas of its work and a disconcerting degree of confusion over its remit.

.. We understand that the ACMD operates within the framework set by the Misuse of Drugs Act 1971 but, bearing in mind that the Council is the sole scientific advisory body on drugs policy, we consider the Council’s failure to alert the Home Secretary to the serious doubts about the basis and effectiveness of the classification system at an earlier stage a dereliction of its duty.On the advice of the ACMD,[citation needed] Home Secretary David Blunkett downgraded cannabis from Class B to Class C in 2004.

[8] The appointment of Dr Hans-Christian Raabe, a prominent member of the Maranatha Community, which aims to "re-establish Christian values in society" received coverage in the British press.

[9] Raabe, a General Practitioner from Manchester, had previously stood as a Christian Peoples Alliance candidate for the North West of England in the European Parliament elections of 2009.

[11] Dr Raabe once argued that "it is futile to pursue discredited policies of so-called 'harm-reduction'",[12] and had written that "The only way of stopping people from dying from drug-related deaths is to prevent drug use in the first place".

[citation needed] Professor David Nutt of the University of Bristol was Chairman of the ACMD until being relieved of his post on 30 October 2009 after criticising politicians for "distorting" and "devaluing" research evidence in the debate over illicit drugs.

[16] Jacqui Smith, then Home Secretary, was also widely criticised by the scientific community for bullying Professor David Nutt into apologising for his comments that, in the course of a normal year, more people die from falling off horses than from taking ecstasy.

[22] His resignation was soon followed by that of Marion Walker, Clinical Director of Berkshire Healthcare NHS Foundation Trust's substance misuse service, and the Royal Pharmaceutical Society's representative on the ACMD.

[24] Within hours of The Guardian revealing this, an article was published online by The Times arguing that Nutt's controversial lecture actually conformed to government guidelines throughout.

[27] A sixth member, Dr Polly Taylor, resigned in March 2010, shortly before the decision to make substituted cathinones - including the legal high mephedrone - illegal.

As well as being extremely unhappy with how the ACMD operates, I am not prepared to continue to be part of a body which, as its main activity, works to facilitate the potential criminalisation of increasing numbers of young people."

[34] Previous Home Secretaries, when responding to the advice of the Advisory Council on the Misuse of Drugs, have all reiterated that the majority of public opinion is against reforming the current stance on prohibition.