"This is your brain," says the white-coated scientist holding an egg, before cracking the shell into a bowl and briskly beating the yolk with a whisk.

"And this is your brain on ecstasy."

The chilling message of the public information film shown on TV in the early-Nineties seemed devastatingly accurate after research concluded the class-A drug was even more dangerous than originally assumed.

Experts writing in the prestigious US journal Science last year suggested taking a single "e" could cause irreversible brain damage and trigger the onset of Parkinson's disease.

They also described the worrying death rate among primates injected with the drug.

Their findings received widespread media publicity, as did horrific pictures of teenager Leah Betts dying in her hospital bed after taking her first pill.

These apparent certainties, however, have been undermined by the scientists' confession this week that a labelling blunder meant their research was based on an entirely different drug, a form of amphetamine.

The results of the study have now been struck from public record.

But Rosie Brocklehurst, of drug support service Addaction in St George's Place, Brighton, thinks people would be foolish to assume they were now safe to enjoy the drug.

Ecstasy addicts account for only four per cent of the users Addaction helps, compared with 28 per cent with alcohol problems and 52 per cent addicted to heroin.

However, Ms Brocklehurst said the symptoms abusers showed were similar to any other kind of addiction and she backed the Government's stance that ecstasy was harmful and should remain illegal.

She said: "Ecstasy is a relatively new drug and we know for sure it causes a risk through dehydration but the long-term effects on the brain are not yet clear.

"We support the Home Office line that ecstasy should remain a class-A drug because we believe it to be dangerous until research proves otherwise."

Michael Morgan, an experimental psychologist at the University of Sussex, has been researching the possible long-term consequences of sustained ecstasy use since 1993.

He believes the discredited US experiment should not be allowed to detract from other vital research.

He said: "In the past, much of the media got the wrong end of the stick by focusing on deaths after taking one tablet.

"They should have been discussing the much broader consequences of prolonged ecstasy use."

His studies have shown habitual users can become excessively-impulsive, develop a poor memory or lose the ability to process complex thoughts, such as forward planning and mental arithmetic.

Dr Morgan said: "The clinical significance of this is still unclear as the problems could be caused by the drug, problems someone has which results in them using ecstasy or something else which could cause both."

This uncertainty can be used by ecstasy supporters who believe it is harmless taken in moderation.

A club promoter in Brighton, who asked not to be named, believes this attitude remains common.

She said: "There are still loads of kids going out on ecstasy, although perhaps not as many as there once were.

"Even if they don't take ecstasy themselves, many know people who do.

"Unless their friend has had a bad experience, I don't think anyone really takes an interest in the bad publicity."

Whether or not sustained use of ecstasy really will scramble your brains like eggs, Dr Morgan is adamant regular pill-popping will lead to damage - both physical and emotional.

He said: "The more you take, the greater the risk of long-term psychological problems."