All kinds of sensory experiences can affect thinking and impair judgement. Drinking, obviously; the inhalation of cannabis; and perhaps even the sight of a new Home Office bill.

The Psychoactive Substances Bill is intended to bring in a very broad ban on “new psychoactive substances”, otherwise known (for now) as “legal highs”. The idea is to clamp down for instance on new sorts of cannabinoids (which mimic the effect of cannabis) and cathinones (a type of stimulant which can mimic the effect of ecstasy) even before they’re invented, so the law doesn’t have to keep playing catch-up. But since it was published, claims have been made that the bill will also ban all sort of familiar things like incense, air fresheners, perfume and even flowers.

Ian Dunt wrote at politics.co.uk that the bill “seems to criminalise the majority of households in the UK”. And as Matthew Scott has written in the Telegraph (arguing that “Theresa May now wants to ban things because they cause pleasure”)

It has even been suggested by the one of the country’s best known legal bloggers, David Allen Green, that the delight produced by the scent of flowers could be enough to engage the provisions of the Bill, and what’s more he is right.

Being no scientist, I’m well aware my ignorance of how substances interact with the brain could easily lead me into error. If others with more knowledge can correct me, I’ll welcome it. But suggestions that the bill will “ban everything” seem to me exaggerated. There may indeed be some problems with the way the bill is drafted – but I don’t think this is one of them.

The definition of a psychoactive substance is in clause 2 of the bill:

(1) In this Act “psychoactive substance” means any substance which—

(a) is capable of producing a psychoactive effect in a person who consumes it, and
(b) is not an exempted substance.

(2) For the purposes of this Act a substance produces a psychoactive effect in a person if, by stimulating or depressing the person’s central nervous system, it affects the person’s mental functioning or emotional state; and references to a substance’s psychoactive effects are to be read accordingly.

(3) For the purposes of this Act a person consumes a substance if the person causes or allows the substance, or fumes given off by the substance, to enter the person’s body in any way.

Notice that under subsection (2) a substance is caught only if it affects thought or feelings by stimulating or depressing the central nervous system. This is the point I think Ian Dunt overlooks when he writes that

The brain is part of the central nervous system and emotions are felt in the brain. Therefore anything you put inside you which changes your emotional or intellectual state satisfies this definition.

A substance is not “psychoactive” under clause 2 just because it stimulates the brain and affects a person’s feelings. It must stimulate the brain and affect your thoughts or feelings by that mechanism.

Music (which I do realise isn’t a substance) stimulates a part of the brain related to hearing – as any sensory experience I think sends a signal which is received in the brain. Music can also lift your mood or depress you, depending on whether it’s Brahms or Boulez. Seeing a bright blue sky stimulates parts of the brain connected with vision, and can cheer you up. Hitting your thumb with a hammer stimulates something in the brain to do with pain, and tends to depress. But none of these things achieves its emotional effect by means of any physical or pharmacological action on the brain itself. Their effect is psychological, achieved I think (I’m open to be persuaded by those who know better) by our learned associations with the brain’s recognition of harmony, clear skies and pain in the thumb.

Lots of things affect our mood in this induced, secondary, non-pharmacological way. Nice smells stimulate the olfactory bulb, which I understand is part of the central nervous system. But nice smells don’t change your mood by the mechanism of stimulating or depressing your central nervous system. They are not in this respect like coffee, cigarettes or wine, whose ingredients really do cross the blood-brain barrier, and whose molecules really do affect us by interacting directly with brain tissue. Coffee, tobacco and alcoholic drinks enjoy specific exemptions under Schedule 1.

Indeed, Matthew Scott himself accepts that not all substances taken into the body act on the brain, when he ridicules the bill’s exemption for “homoeopathic medicinal products”:

A pointless exemption has been given to homoeopathic preparations, even though there is no chance whatever that the silly little pills of nothingness and quackery would have any effect on your brain anyway, except as a placebo.

This reveals that even Matthew cannot think every nice thing falls within clause 2. Water tastes good, and can certainly cheer you up. It has the same sort of secondary emotional effects as the smell of flowers. But once you accept that water (or any other “inactive” ingredient or placebo) is not psychoactive because incapable of having any effect on the brain except by a psychological mode of action, you have already stepped back from the strong claim that the bill “bans pleasure”. If everything pleasant really were banned under clause 2, then an exemption for homoeopathic products consisting entirely of water would not be pointless at all. Matthew himself identifies the distinction that undermines his argument.

It’s not right, then, simply to say clause 2 catches everything that smells nice and lifts your mood, like flowers or everyday perfume.

To be clear, I am not arguing that perfumes or plants are “exempt” from the bill. An offence could be committed under the bill if some new psychoactive substance contained in perfume were capable of being delivered to the brain through the nose, and acting on it. And an offence could conceivably be committed by supplying a plant with a fragrance that acted in the same way. My point is that clause 2 of the bill does not simply cover every nice-smelling thing behind the perfume counter or at the local florist.

You might argue that the current wording of the bill does not adequately target the distinction I’m making between substances that act physically on the brain, and those whose effects are secondary. But clause 2, which covers only substances that affect mental functioning or emotional state by stimulating or depressing the central nervous system, arguably does the job well enough; and I think courts are likely to interpret it as doing so.

But there’s another reason why, even if something really does act on the central nervous system, it’s still not necessarily “banned”. For one thing, the bill will not criminalise its possession or use at all. What’s more, not even its production or supply will necessarily be prohibited.

There’s an offence of supplying a psychoactive substance, under clause 5(1):

A person commits an offence if—

(a) the person intentionally supplies a substance to another person,
(b) the substance is a psychoactive substance,
(c) the person knows or suspects, or ought to know or suspect, that the substance is a psychoactive substance, and
(d) the person knows, or is reckless as to whether, the psychoactive substance is likely to be consumed by the person to whom it is supplied, or by some other person, for its psychoactive effects.

Let’s take as our example products containing frankincense, which I understand (I’m grateful to Nelson Jones for telling me) has been shown to have psychoactive effects. If you buy a product containing frankincense, the retailer will have intentionally supplied a substance to you, so satisfying subsection (a); and it, or the frankincense in it, will be a psychoactive substance, so satisfying subsection (b).

It’s not quite so clear that the retailer ought to know or suspect frankincense has psychoactive effects, so satisfying subsection (c). But even supposing he or she ought to suspect this, subsection (d) would still present a serious problem for any prosecution.

While some customers might know frankincense has potential antidepressant effects and buy it precisely for that reason, that’s not actually why most people buy incense. Most of us buy incense simply because we think it smells nice, or perhaps as an aid to meditation. Even if we think it may have psychoactive effects (as I suppose I do, now), we don’t buy it for those effects. So we can’t say the retailer knows we’re likely to want it because of them.

That leaves recklessness. Admittedly, if the retailer does happen to know the incense is psychoactive, he or she will be aware we might want it for its psychoactivity and may even think it likely that we do (which I think is what “recklessness as to likelihood” in subsection (d) requires). But it still doesn’t follow that supplying us with the incense would be reckless.

Recklessness in law is not simply doing something that you’re aware involves risk. It’s accepting a risk unreasonably. As Lord Bingham explained in the House of Lords in 2003 in R v G (see para. 41)

A person acts recklessly … with respect to –
(i)  a circumstance when he is aware of a risk that it exists or will exist;
(ii)  a result when he is aware of a risk that it will occur;
and it is, in the circumstances known to him, unreasonable to take the risk.

Here, I think we’re talking about recklessness as to the circumstance that a substance is “likely to be consumed … for its psychoactive effects”.

So even if a retailer really did suspect us of wanting to fill our lounge with incense in the hope of easing depression, selling it to us wouldn’t be reckless in respect of that likelihood. The retailer knows incense is burned and its smoke inhaled all over the world without ill effects, by and large. It’s therefore reasonable to sell it in spite of the likelihood we’ll try using it as an ambient anti-depressant.

It might be argued (as Professor James Chalmers has suggested on Twitter) that what I’m doing here is reading in to the bill a “harm test” that simply isn’t there. But I disagree. Any alternative interpretation, dropping the requirement for risk-taking to be unreasonable, would be a strange approach to recklessness. On that approach major surgery and motorway driving would always be reckless, since they involve knowingly running serious risks. I’m not reading in a “harm test”: my approach is an orthodox application of the recklessness test explicitly written in to the bill.

If I’m correct then even if they really were psychoactive (I think not), and even if it were suspected a customer was likely to try getting high on them (surely a rare suspicion), selling flowers or Chanel No. 5 would be reasonable and therefore lawful.

Having poured cold water on some of the claims made about the bill, let me turn to some concerns I think may be real. They relate to how, on its face, the bill treats two particular types of psychoactive substance.

The first are substances that aren’t risky, but which seem to have demonstrable psychoactive effects and are typically used because of our belief in them. Lavender oil may be a good example. As I understand it there is some evidence that linalool, which is contained in lavender, has anaesthetic, depressant effects. And of course many people do buy lavender precisely because they think it will be calming – helping them go to sleep if they put a few drops on their pillow, for example.

A retailer selling lavender oil – at least when marketed in the context of aromatherapy rather than as (say) a moth repellent – surely knows most customers are using it for what they think are its calming effects. Indeed, Boots’ packaging of lavender oil says it’s “to help relax and soothe”. In these circumstances, the fact that it may actually have demonstrable psychoactive effects means all elements of the clause 5(1) offence are potentially satisfied. The retailer may be supplying a psychoactive substance and ought perhaps to suspect it to be psychoactive; and he or she knows the customer wants it for that very reason. A typical retail supply of lavender oil would indeed appear to be unlawful on the face of the bill. And depending on the scientific evidence, Matthew Scott may have a point about hop pillows.

The other type of substance I’m concerned about is those that have legitimate household uses but are known sometimes to be used for their psychoactive effects, and to be risky. Glue and solvents are the obvious examples.

I don’t think a retailer selling a glue or solvent would ordinarily commit an offence under clause 5(1) as it’s drafted. Yes, the retailer would intentionally supply a psychoactive substance knowing it to be psychoactive. But the retailer would not know the customer wanted it for that effect (unless the customer said so); nor would the retailer be reckless in most cases. The requirement of recklessness

as to whether the psychoactive substance is likely to be consumed … for its psychoactive effects

means in my view that the supplier must suspect that the glue or solvent is likely being bought for sniffing. If that’s right, the retailer could only sell recklessly if it seemed the particular customer at the counter might well be buying the product for that reason. That would obviously be a minority of cases. So, while an individual sale could indeed amount to the clause 5(1) offence, sales of glue would not in any general sense be “banned”.

But manufacturers, importers and wholesale suppliers of glue and solvents are in a more problematic position. They knowingly sell psychoactive substances to other businesses. And while their trade customers (Sainsbury’s, for instance) aren’t the sort of “person” who’s even capable of sniffing glue, manufactures and wholesalers must know there’s a risk that a part of any large order is eventually

likely to be consumed … by some other person for its psychoactive effects

to quote section 5(1)(d). The greater the quantity they sold to a trade customer in fulfilment of any order, the more obvious this risk would be.

The only ways of escaping liability would be either an argument that no order fulfilled was so big that any single unit was likely to be sniffed by an end user; or an argument that knowingly engaging in wholesale supply was reasonable so not reckless, given that glue and solvents are overwhelmingly used properly and given the “downstream” safeguard of retailers’ duty not to sell recklessly. Those arguments might work; but I can imagine manufacturers and wholesalers being slightly worried by the bill.

A similar problem may apply to wholesalers of lavender oil, and manufacturers of both types of product may risk committing the clause 4 offence of producing a psychoactive substance.

I’m not sure what I think about drugs policy. I have sympathy for the view that we should legalise and regulate at least some drugs, and focus on tackling the health problems they cause. At the same time I doubt that would be a panacea, and understand why legal prohibitions may be indispensable. It’s not obvious to me that this bill is stupid, and something like it seems to have been working acceptably in Ireland.

There may be problems on the face of the bill, which will benefit from close scrutiny. We need to know whether or not ministers intend to affect trade in products like glue and lavender oil, and if not how they can reassure the industries affected. One way might be to make businesses like these exempted activities, in regulations made under clause 10.

But I really don’t think the bill bans perfume, incense or flowers.