In the long and tortured debate over drug policy, one of the strangest episodes has been playing out this fall in the United Kingdom, where the country’s top drug adviser was recently fired for publicly criticizing his own government’s drug laws.

The adviser, Dr. David Nutt, said in a lecture that alcohol is more hazardous than many outlawed substances, and that the United Kingdom might be making a mistake in throwing marijuana smokers in jail. His comments were published in a press release in October, and the next day he was dismissed. The buzz over his sacking has yet to subside: Nutt has become the talk of pubs and Parliament, as well as the subject of tabloid headlines like: “Drug advisor on wacky baccy?”

But behind Nutt’s words lay something perhaps more surprising, and harder to grapple with. His comments weren’t the idle musings of a reality-insulated professor in a policy job. They were based on a list - a scientifically compiled ranking of drugs, assembled by specialists in chemistry, health, and enforcement, published in a prestigious medical journal two years earlier.

The list, printed as a chart with the unassuming title “Mean Harm Scores for 20 Substances,” ranked a set of common drugs, both legal and illegal, in order of their harmfulness - how addictive they were, how physically damaging, and how much they threatened society. Many drug specialists now consider it one of the most objective sources available on the actual harmfulness of different substances.

That ranking showed, with numbers, what Nutt was fired for saying out loud: Overall, alcohol is far worse than many illegal drugs. So is tobacco. Smoking pot is less harmful than drinking, and LSD is less damaging yet.

Nutt says he didn’t see himself as promoting drug use or trying to subvert the government. He was pressing the point that a government policy, especially a health-related one like a drug law, should be grounded in factual information. In doing so, he found himself caught in a crossfire that cost him the advisory post he had held for a decade.

The same issue is becoming a hot one in America - this fall the Obama administration took a baby step toward easing federal scrutiny of medical marijuana use, and a policy report due early next year is expected to emphasize addiction prevention and treatment over criminal enforcement. Opponents are already attacking the administration for its laxity, but Thomas McLellan, a newly installed White House drug official, has begun loudly pushing for policy that incorporates more science.

“We must increase the use of evidence-based tools at our disposal,” McLellan said in an interview last week.