Earlier this week Prof Nutt used a lecture at King's College, London, to attack what he called the "artificial" separation of alcohol and tobacco from illegal drugs.
The professor said smoking cannabis created only a "relatively small risk" of psychotic illness, and claimed those who advocated moving ecstasy into Class B had "won the intellectual argument".
Public concern over the links between high-strength cannabis, known as skunk, and mental illness led the government to reclassify cannabis to Class C last year.
In the past, Prof Nutt has also claimed that taking ecstasy is no more dangerous than riding a horse.
Now it's perfectly true that if alcohol had just been synthesised in the lab for the first time, and tobacco and smoking had just been brought across the sea from some exotic empire (note that King James I (VI of Scotland), while disapproving, didn't criminalise tobacco use), it's likely they would be made illegal. On a strict damage-from-use basis, the Prof stands on unassailable high ground.
But that isn't where we find ourselves. Smoking has a 400-year history in these islands - the use and abuse of alcohol goes back to our prehistory. Dope as a mainstream drug goes back thirty or forty years (yes, I know about Queen Victoria, laudanum and all that), ecstasy 20 or so. There's a cultural reason why riding a horse is socially acceptable round my way and dropping an E isn't - people have been doing the former for a lot longer.
(There's a useful little paper on alcohol and history by Prof Virginia Berridge here. And wasn't James I full of good logic and observation ? 'oftentimes in the inward parts of men fouling and infecting them with an unctuous and oily kind of soot as hath been found in some great tobacco-takers that after their death were opened').