The deafening chorus of criticism over the psychoactive substances bill grew even louder today when the home secretary's own drug advisers launched a blistering attack on it.

It's damning stuff. They found that what the legislation intends to do is "impossible" and that "psychoactivity", the very effect the bill is trying to outlaw, "cannot be unequivocally proven". They are singing from the same hymn sheet as all the chemists, legal experts and sensible commentators who have looked at it. This is a Micky Mouse bill, dealing with a cartoonish reality which bears no connection to the way substances interact with the human body in the real world.

Will it make a difference? Undoubtably not. One of the primary functions of the psychoactive substances bill is to sideline the council, mostly because it keeps on doing things like this. The council works on the basis of evidence gathering and assessment of harm, both concepts which the bill turns its back on. But it is still worth looking at the council's eight objections, which offer a concise account of some, but by no means all, of the problems in the bill.

1) The omission of the word 'novel' has widened the scope of the bill beyond that originally intended.

The council is no libertarian think tank. It actually supports a blanket ban on new psychoactive substances. But even from this very conservative perspective, the government's position still looks barmy. As the council says:

"It is almost impossible to list all possible desirable exemptions under the bill. As drafted, the bill may now include substances that are benign or even helpful to people, including evidence-based herbal remedies that are not included on the current exemption list."

Proving specfied psychoactive causation will be almost impossible in court, experts believe

2) The psychoactivity of a substance cannot be unequivocally proven

Here's the point made endlessly by scientists or anyone with even a passing understanding of pharmacology: you cannot test the causal mechanism for psychoactive effect in court. The government wants a mechanistic way of describing how something hits the central nervous system and then affects mood and thought, but there's no way of documenting that without resorting to talk of 'brain' and 'mind', and even if there was, plenty of substances we don't want to target - like taurine, nutmeg or incense - would be covered by it too. As the council says, rather dryly:

"The only definitive way of determining psychoactivity is via human experience, which is usually not documented."

3) The bill uncouples the concept of harm from control of supply, importation and production

This seems simple. Why doesn't the government insert the word 'harmful' into its definition of psychoactive substance, thereby getting rid of nonsense examples like nutmeg above? Because to do so brings back evidence and testing to a law which is intended to eradicate them from drug policy.

The Home Office realises the danger of reason in an unreasonable pursuit. 'Harm' tests act as a thin end of the wedge for a liberal drug policy, because once you show that a drug is essentially harmless, as laughing gas is, you have to accept its legitimate use. This strain of thought has long been present in the Home Office. After all, the council's former chairman, David Nutt, was sacked for, among other things, outlining the statistical similarity between the dangers of horse-riding and ecstasy. For drug prohibition to continue it is essential that the reality of harm is not documented or taken into consideration. As the council says:

"Without the inclusion of the words 'harmful' or 'potentially harmful', the ACMD can envisage situations whereby the supplier of benign or beneficial substances could be prosecuted under the bill."

The Home Office doesn't care.

Scientific bodies have warned the bill could severely limit research into new medical drugs

4) The bill could seriously inhibit medical and scientific research on psychoactive substances.

The council concedes that there's an exemption for psychoactive substances in clinical trials, but points out there's no exemption for laboratory research in academia or industry. Many scientists, particularly in universities, are extremely worried about this. As prominent scientists wrote to the home secretary last week, a researcher who develops a new substance which could help combat depression will currently be in contravention of the law if they do volunteer trials.

5) The bill has the potential to both criminalise and apply disproportionate penalties to many otherwise law abiding young people and adults.

One of the few things thing the bill did right was not criminalise possession – just production and supply. But the legal definition of supply stretches much further than people think it does. If one guy goes online to buy this stuff and then shares it with his mates, that's supply. As the council says:

"The ACMD believes that criminal justice sanctions would be disproportionate to the harm caused by such acts. The inclusion of social supply in the bill also has the potential to result in discriminatory impact on members of black and minority ethnic groups, given what is known about the over-representation of members of these groups at each stage of the criminal justice response to drug offences."

6) The bill is likely to lead to the closure of many 'headshops', the reduction of the direct sale of novel psychoactive substances to children, and the 'normalisation' of sale of these substances in shops. However, the evidence-base for individual supply reduction interventions on a market is poor and the evidence that there is indicates that disrupting a supply market often leads to displacement of that market.

As has been well documented, the war on drugs is like a balloon full of air. Squeeze one bit and it expands elsewhere. That's true for trade routes and it's true for drug provision too. The bill will kill headshops – the council is right about that – but that trade will not disappear. As with other drugs, it will go to the dealers and, increasingly, the online marketplaces. Once the trade goes underground it is even harder to communicate with those who need safety information about the substances they are consuming.

Owners of bars could be liable to prosecution for allowing in legal highs

7) 'Directors' of many premises and venues may be liable to prosecution for 'supplying and/or importing' novel psychoactive substances

The law of unintended consequences. The bill makes 'directors' of premises where the drugs are taken or supplied liable to prosecution. But most of these legal highs don't show up on drug tests (which, incidentally, is why their use in prison has soared) and they're not recognised by drug dogs. So if the law is properly enforced we can expect to see a tidal wave of prosecutions against bars, pubs, nightclubs, hostels, prisons and festivals. And that's not even to mention residential property.

8) The bill would have a substantial impact on the sale of many herbal medicines.

Plenty of herbal medicines are useless and function as an informal tax on gullibility. Some have evidence of being beneficial. Most are not registered, which would grant them an exemption. So regardless of whether they are slightly useful or not, they are about to be needlessly wiped out by a law which was never intended to have anything to do with them.

Almost every expert who casts their eye over this bill comes away startled by its stupidity and certain that it will not work. It would either involve arresting everyone - all prison governors, all bar owners, everyone who sells incense, the list goes on - or, more likely, as in Ireland it will involve arresting no-one.

The chorus of criticism is deafening. The only place where the bill has not faced any substantial criticism at all is in the Commons chamber. And it will likely stay that way until it is passed. MPs have no interest in evidence. And that partly explains how this bill could be allowed to exist in the first place.