The panel will review the latest evidence before making its decision
The body that advises the government on illegal drugs is meeting to discuss whether ecstasy should be downgraded from a Class A drug to Class B.
Senior police officers have written to The Advisory Council on the Misuse of Drugs urging it to leave ecstasy as a Class A drug, the BBC has learned.
Incoming head Prof David Nutt has said ecstasy is less harmful than cocaine or heroin and should be reclassified.
Ministers ignored a recommendation in May, by moving cannabis up to Class B.
The meeting over ecstasy could set the government on another collision course with the Advisory Council, should it recommend reclassification.
The panel will review the latest evidence before making its decision.
As part of the discussions, panel members will consider the submission from the Association of Chief Police Officers (Acpo), stating that transferring ecstasy to class B would send out an "unfortunate message".
"From an operational policing perspective, Acpo does not support any change in classification of ecstasy from its current class A status," said Tim Hollis, chief constable of Humberside Police and Acpo's lead officer on drugs.
A Home Office spokesman said the government firmly believed ecstasy should remain a Class A drug.
"Ecstasy can and does kill unpredictably. There is no such thing as a 'safe dose'," he said.
An estimated 250,000 people in England and Wales take ecstasy every month.
About 50 deaths a year involve the use of ecstasy - known to chemists as MDMA - in England and Wales, according to the Office for National Statistics. Figures showed there were 246 deaths between 2003 and 2007.
Professor Colin Blakemore, from Oxford University and the UK Drug Policy Commission, said all drugs were dangerous but that the issue was one of "relative harm".
"The problem, one of the problems, is the assumption that if the advisory council recommends that ecstasy should be downgraded they're in a sense encouraging people to use it - that's not the case at all.
"They are simply making a statement about the relative damage associated with ecstasy compared with crack cocaine and heroin, where it is at the moment."
The Transform Drug Policy Foundation, a charity that says prohibition is the major cause of drug-related problems, said this latest review would only result in "little more than posturing on all sides".
A spokesman said: "Given that the government overruled the council on cannabis reclassification, the entire exercise is doomed before it has begun."
The penalties for possession and supply of a Class A drug are the most severe.
HAVE YOUR SAY
Compared to drugs we allow to be sold over the counter, ecstasy is really quite safe, and it doesn't matter if you don't want that to be true.
Dr Reece Walker, London UK
Possession carries a maximum sentence of up to seven years in prison, an unlimited fine or both.
Dealers face a maximum term of life imprisonment, an unlimited fine or both.
Possession of Class B drugs carries a maximum prison sentence of five years, while dealing can attract a term of up to 14 years.
In 2006 a report by the Select Committee on Science and Technology recommended drugs should be rated purely on the basis of health and social risks and not legal punishments.
It said alcohol and tobacco should be included in the ratings system.
In May, Home Secretary Jacqui Smith announced plans to reclassify Cannabis as a Class B drug.
This was despite the council stating it should remain as Class C.