The ACMD was set up to advise the government on drug misuse
The Advisory Council on the Misuse of Drugs (ACMD) is an independent expert body that advises government on drug-related issues in the UK.
It was established under the Misuse of Drugs Act 1971 during Edward Heath's Conservative government.
It makes recommendations on the control of dangerous or otherwise harmful drugs, including classification and scheduling under the 1971 Act and its regulations.
The ACMD website says that it considers "any substance which is being or appears to be misused" and "which is having or appears to be capable of having harmful effects sufficient to cause a social problem".
Its members are unpaid, although their expenses are covered, and they meet twice a year.
They include representatives from the medicine, dentistry, veterinary medicine, pharmacy, the pharmaceutical industry and chemistry, along with members who have relevant experience of social problems connected with the misuse of drugs, such as police officers.
Before the departures of Prof David Nutt, Dr Les King and Marion Walker, there were 31 members on the council, almost all of whom were due to end their posts on 31 December 2010.
Prof Nutt was named chairman designate of ACMD in May 2008 and took over the post in November last year.
The ACMD has previously issued such reports as Drug Misuse among Children of School Age in 1977, Security of Controlled Drugs in 1983, and Drug Misuse and the Environment in 1998.
In 1978 the ACMD recommended downgrading cannabis from class B to C, but Labour Home Secretary Merlyn Rees rejected the advice.
In 2002, at the request of then Home Secretary David Blunkett, the council again examined the status of cannabis. Mr Blunkett accepted the recommendation to downgrade it from B to C, on grounds it was less harmful than class B drugs such as amphetamines.
But in 2008 Home Secretary Jacqui Smith rejected advice from the ACMD to keep cannabis at class C after a review concluded that evidence of a link between mental illness and stronger strains of cannabis remained weak.
And in February 2009 she vetoed the recommendation that ecstasy be downgraded from class A, after a review of 4,000 papers on the subject.
In 2008, the ACMD also urged Jacqui Smith to set a "zero rate" for younger drivers, meaning that any driver under 21 could not drink any alcohol at all.
It has previously called for calories to be placed on alcohol labels, to warn customers how fattening drinks are and even to compare them with junk food.
It has also suggested a ban on selling strong lagers and beers and taxing drinks on the basis of their strength to reduce binge drinking.