Today sees the publication of two pieces of scientific research that threaten to destabilise further the orthodoxy on drug policy in Britain.

One says our classification system of illicit substances is basically hopeless. The other says that decriminalising illicit drugs may be quite a good idea.

Tomorrow, of course, Californians vote on whether to legalise marijuana.

It is almost exactly a year since this blog revealed that Professor David Nutt had been sacked from his position as chair of the Advisory Council on the Misuse of Drugs (ACMD) by the then Home Secretary Alan Johnson.

His dismissal, for allegedly "campaigning" against government drugs policy, prompted a show-down between scientists and ministers which saw a further seven council members resign.

A number of those experts went on to found their own Independent Scientific Committee on Drugs, operating, as they put it, "free from the constraints of policy-making and politics".

Today an ISCD paper entitled Drug Harms in the UK: A Multicriteria Decision Analysis is published in the Lancet. Its title may not be overly exciting but its findings are bound to cause an almighty stir.

The headline is that, on the basis of new analysis assessing the relative harms of different legal and illegal drugs to the user and wider society, "alcohol was the most harmful drug (overall harm score 72), with heroin (55) and crack (54) in second and third places".

The professor helped produce an earlier version of what is called a "harm matrix" of drugs. As today's paper puts it, that "provoked major interest and public debate, although it raised concerns about the choice of the nine criteria and the absence of any differential weighting of them".

So the ISCD has returned to the fray with what is called multi-criteria decision analysis.

This approach includes 16 criteria including a drug's affects on users' physical and mental health, social harms including crime, "family adversities" and environmental damage, economic costs and "international damage".

The scientists, based on their expert knowledge, score a substance on each category from zero to 100.

The problem remains, however, of how much weight to give each of these categories.

"The weighting process is necessarily based on judgement, so it is best done by a group of experts working to consensus," the report authors say.

"Extensive sensitivity analyses on the weights showed that this model is very stable; large changes, or combinations of modest changes, are needed to drive substantial shifts in the overall rankings of the drugs."

What emerges is a ranking of drugs at complete odds with the official Home Office classification system.

The fact that alcohol emerges as the most harmful drug leads the authors to conclude that "aggressively targeting alcohol harms is a valid and necessary public health strategy" but its place at the head of the table also suggests a legal status in stark contrast to the much less harmful effect of Class A drugs including ecstasy and LSD.

It is also notable that cocaine and tobacco emerge with very similar rankings in terms of harm.

"Our findings lend support to previous work in the UK and the Netherlands, confirming that the present drug classification systems have little relation to the evidence of harm," they say.

Also published today is another peer-reviewed paper assessing the effect of Portugal's decision to decriminalise all illicit drugs. You may recall I visited the country last year to report on a policy introduced in 2001.

Since then there has been a dispute as to how effective the new arrangements have been. I have seen all kinds of pretty half-baked analysis attempting to prove that the policy is either the silver bullet to drug abuse or that it has been a health and crime disaster.

Well, this new report looks at the arguments of both sides and attempts to provide a critical analysis of what has happened and concludes that "contrary to predictions, the Portuguese decriminalization did not lead to major increases in drug use. Indeed, evidence indicates reductions in problematic use, drug-related harms and criminal justice overcrowding."

The report goes on to point out that "such affects can be observed when decriminalising all illicit drugs. This is important, as decriminalisation is commonly restricted to cannabis alone".

The Home Office has not yet responded to the new study but drugs minister James Brokenshire recently told the House of Commons "[O]n the specific point about the Portuguese model, we are against that proposal."