Next week Professor David Nutt will test the effects of MDMA – otherwise known as ecstasy – on a number of volunteers live on TV in a research project funded by Channel 4. Julia Manning, chief executive of thinktank 2020Health believes the experiment is reckless. Oliver Laughland chairs.

David Nutt: The project has two purposes. The first is to show the whole process – from design to analysis – of a scientific experiment being performed. The second is to do the first UK imaging study of the human brain with [the effects of] MDMA, using the latest technology. The drug has been around for 50 years, and been used massively by young people. It also has important therapeutic potential and it's necessary, from the perspective of a neuroscientist, to understand what it does in the brain.

Julia Manning: It's reckless and pointless. We have a high regard for British scientific research. But I was alarmed when I heard about this. I don't believe it is a serious scientific study. It's been funded by Channel 4 because the Medical Research Council (MRC) and other authoritative bodies wouldn't fund it.

DN: The research quality in this study is world-leading, using cutting-edge neuro-imaging technology and analysis. It will be published in the highest-quality journals. It's being funded by a television company not because other funders don't value the qualities of the research. When we put this study as part of a larger project to the MRC, it was scored very highly, but didn't fit in with the MRC's portfolio of addiction. As we know, MDMA is not addictive. I should be commended for finding a way of doing quality science, which otherwise wouldn't happen.

JM: Simply because you're using high technology doesn't make it quality. I also dispute that MDMA isn't addictive, because it's an amphetamine and it's well-known that amphetamines are addictive. Ecstasy and other drugs are illegal for good reasons. Not just for scientific reasons – it's because of the social, economic and moral messages that it sends out as well.

Oliver Laughland: Do you think the programme will send out the wrong moral message?

DN: I don't think a scientific programme has any relationship to moral messages. What we're trying to do is understand the effects on the brain of a drug which, as everyone who uses it – by and large – tells us, produces an interesting and profound change in people's feelings in a positive direction. This science will give us an insight into a brain mechanism underpinning trust, empathy and love, and may lead us to new therapies. I am president of the British Neuroscience Association; I know what good neuroscience is, and this is cutting-edge.

JM: It's publicity-seeking neuroscience. It's publicity-seeking neuroscience. The issue is that you're using an illegal drug to get publicity for your research and position, which is wanting to legalise access to [some] drugs. If you're really looking to do serious neuroscience, why aren't you looking for a cure for Alzheimer's or Parkinson's?

DN: Sorry, Julia, but depression is still – as you may know from the recent report from the European Brain Council, of which I'm vice president – the largest cause of disability in Europe. We have many treatments that are not particularly effective. I'm looking to innovate. You should be endorsing this approach and encouraging the British pharmaceutical industry to support me. The reason it is not is because it is too terrified of the illegal status of these drugs – it believes, incorrectly, that working in this field would give it bad publicity. Your argument with me is essentially fuelling that prejudice.

JM: That's absolutely not the case. The University of Birmingham is using a derivative of MDMA [in a modified form to examine its effects on fighting blood cancer cells]. It has got a licence from the Home Office. Have you got one?

DN: Of course we have. Are you saying that fighting cancer is more important than depression? That it's all right to use illegal drugs for cancer but you can't use them for depression or trauma illness? The illegality is a separate dimension. There are drugs that are very useful but also illegal; drugs such as opiates, ketamine, amphetamines – all of which are prescribable for medical conditions. My view is clear. If this drug has therapeutic utility, doctors should be able to use it.

JM: This sends the wrong message to the public and to young people because it implies that taking MDMA as it is currently constituted, could be valid for therapeutic use. The other examples that you cited have medically approved, trialled and tested forms in which the risks have been considered to be less than the benefits. That is the basis of all our medicine. There is no restriction on doing proper trials on drugs that are available as illegal forms. If you come up with a valid scientific study, the MRC and the Home Office will often give approval to looking into possible therapeutic uses for those drugs – often in different forms, not in their street form. The law is in place to protect and that is important. What this programme will do is glamorise the taking of MDMA.

DN: This is something we thought about very carefully. I'm not in favour of taking any [illegal] drugs, which is why I'm concerned about the glamorising of the taking of alcohol in many aspects of our society. I am anti-drugs, and my entire research career has been directed towards understanding the harms of drugs so we can minimise them. I'm not in the business of glamorising anything. You will see when you watch the show that it's extremely rigorous. It will tell us where MDMA works in the brain, whether there is a biological relationship between taking MDMA and the three-day blues [come down] – which I can tell you now there isn't. It will make the data even stronger on how this drug might be useful in post-traumatic stress disorder.

OL: Won't showing you taking this drug in a controlled environment go some way to demystifying its use? It's a fact of life for thousands of young people.

JM: I don't think drugs are a fact of life. Only three million adults have tried drugs. Use of drugs is symptomatic of profound malaise; we are letting down young people and children if we imply taking drugs is something that could have value. It's not the drugs that are in question, it's the human, psychological and existential issues complicit in drug-taker behaviour that we should be raising.

DN: These people [taking part in the experiment] are taking a chemical that's 99.9% pure ecstasy. This is not street drugs, this is the pure form that could be used therapeutically. I was working with the Home Office when people began to get concerned about the harms of ecstasy in the 1990s. Now I realise this was due to a misunderstanding of how to use the drug, and gross exaggeration by the media. I realise now that the drug is far less harmful then I believed at the time. Putting it into class A was wrong, it was politically motivated. It's been vilified.

JM: We don't agree that you can look at a drug by itself. You have to consider the social, moral and economic implications of doing anything that suggests taking a banned substance is OK.

Drugs Live: The Ecstasy Trial is on Channel 4 at 10pm on Wednesday and Thursday next week