The government's chief drugs adviser has strongly indicated the Advisory Council on the Misuse of Drugs (ACMD) will recommend mephedrone be banned.
He said he believed mephedrone was "harmful" and hinted that it should be categorised as a Class B drug.
His evidence to an MPs' committee comes as the deaths of a number of young people have been linked to the drug.
The drug is known by various names, including "M-Cat", "MC", "mieow", "meow", "4MMC" or simply plant fertiliser.
Concern over its effects has grown after two friends, Louis Wainwright, 18, and Nicholas Smith, 19, died in Scunthorpe, Lincolnshire, last week after taking mephedrone.
Since then a number of other deaths have been investigated to see if they are connected to the drug, including that of a 24-year-old woman who died in North Yorkshire on Monday.
It is usually a white or yellowish powder, which is snorted, but it can also be obtained in pills and capsules. It is marketed as a plant food.
The professor told the Home Affairs Select Committee said it was his personal view as a pharmacologist that mephedrone and other related drugs were "amphetamines by another name".
Amphetamines are currently classified as Class B drugs and possession can carry a jail term of up to five years or an unlimited fine or even both.
He also said that if the ACMD does recommend a ban it will recommend "a generic scope that will cover all derivatives of mephedrone - either those made now or those that could be made in the future".
Prof Iversen said it would be a "tragedy" if anyone else died from mephedrone before the ACMD issued its report.
He said a plan by Liverpool John Moores University to use students as guinea pigs in a research experiment on the drug was "pretty unethical".
Psychologists at the university have recruited 50 students for a study into the effects of mephedrone.
Prof Iversen admitted there was a "temporary hiatus" in the ACMD's review of mephedrone following the dismissal of Professor David Nutt last year and the resignations of other ACMD members over government policy on cannabis.
He said there were three vacancies on the ACMD's statutory list of positions which he said would be filled by Monday.
Prof Iversen also revealed that last year he too was "on the verge" of resigning as a member of the ACMD with a "number of colleagues" - because the relationship between the ACMD and Home Secretary Alan Johnson had deteriorated.
However he said was satisfied with the current relationship, and said he was "confident" the body's independence would be fully safeguarded.
Websites selling the drug have told their customers it is a case of "when" not "if" mephedrone will be banned.
BBC News Website
Tuesday, 23rd March, 2010