Jan. 23, 1969. LORD REID stated the facts and continued: My Lords, a Divisional Court dismissed her appeal, holding that she had been concerned in the management of those premises. The reasons given for holding that she was managing the property were that she was in a position to choose her tenants: that she could put them under as long or as short a tenancy as she desired: and that she could make it a term of any letting that smoking of cannabis was not to take place. All these reasons would apply to every occupier who lets out parts of his house or takes in lodgers or paying guests. But this was held to be an absolute offence, following the earlier decision in Yeandel v. Fisher
 1 Q.B. 440.
How has it come about that the Divisional Court has felt bound to reach such an obviously unjust result? It has in effect held that it was carrying out the will of Parliament because Parliament has chosen to make this an absolute offence. And, of course, if Parliament has so chosen the courts must carry out its will, and they cannot be blamed for any unjust consequences. But has Parliament so chosen?
I dealt with this matter at some length in Warner's case
 2 A.C. 256. On reconsideration I see no reason to alter anything which I there said. But I think that some amplification is necessary. our first duty is to consider the words of the Act: if they show a clear intention to create an absolute offence that is an end of the matter. But such cases are very rare. Sometimes the words of the section which creates a particular offence make it clear that mens rea is required in one form or another. Such cases are quite frequent. But in a very large number of cases there is no clear indication either way. In such cases there has for centuries been a presumption that Parliament did not intend to make criminals of persons who were in no way blameworthy in what they did. That means that whenever a section is silent as to mens rea there is a presumption that, in order to give effect to the will of Parliament, we must read in words appropriate to require mens rea.
Where it is contended that an absolute offence has been created, the words of Alderson B. in Attorney-General v. Lockwood(1842) 9 M. & W. 378, 398 have often been quoted:
“The rule of law, I take it, upon the construction of all statutes, and therefore applicable to the construction of this, is, whether they be penal or remedial, to construe them according to the plain, literal, and grammatical meaning of the words in which they are expressed, unless that construction leads to a plain and clear contradiction of the apparent purpose of the Act, or to some palpable and evident absurdity.”
That is perfectly right as a general rule and where there is no legal presumption. But what about the multitude of criminal enactments where the words of the Act simply make it an offence to do certain things but where everyone agrees that there cannot be a conviction without proof of mens rea in some form? This passage, if applied to the present problem, would mean that there is no need to prove mens rea unless it would be “a plain and clear contradiction of the apparent purpose of the Act” to convict without proof of mens rea. But that would be putting the presumption the wrong way round: for it is firmly established by a host of authorities that mens rea is an essential ingredient of every offence unless some reason can be found for holding that that is not necessary.
It is also firmly established that the fact that other sections of the Act expressly require mens rea, for example because they contain the word “knowingly,” is not in itself sufficient to justify a decision that a section which is silent as to mens rea creates an absolute offence. In the absence of a clear indication in the Act that an offence is intended to be an absolute offence, it is necessary to go outside the Act and examine all relevant circumstances in order to establish that this must have been the intention of Parliament. I say “must have been” because it is a universal principle that if a penal provision is reasonably capable of two interpretations, that interpretation which is most favourable to the accused must be adopted.
What, then, are the circumstances which it is proper to take into account? In the well known case of Sherras v. De Rutzen
 1 Q.B. 918 Wright J. only mentioned the subject matter with which the Act deals. But he was there dealing with something which was one of a class of acts which “are not criminal in any real sense, but are acts which in the public interest are prohibited under a penalty” (p. 922). It does not in the least follow that when one is dealing with a truly criminal act it is sufficient merely to have regard to the subject matter of the enactment. One must put oneself in the position of a legislator. It has long been the practice to recognise absolute offences in this class of quasi-criminal acts, and one can safely assume that, when Parliament is passing new legislation dealing with this class of offences, its silence as to mens rea means that the old practice is to apply. But when one comes to acts of a truly criminal character, it appears to me that there are at least two other factors which any reasonable legislator would have in mind. In the first place a stigma still attaches to any person convicted of a truly criminal offence, and the more serious or more disgraceful the offence the greater the stigma. So he would have to consider whether, in a case of this gravity, the public interest really requires that an innocent person should be prevented from proving his innocence in order that fewer guilty men may escape. And equally important is the fact that fortunately the Press in this country are vigilant to expose injustice and every manifestly unjust conviction made known to the public tends to injure the body politic by undermining public confidence in the justice of the law and of its administration. But I regret to observe that, in some recent cases where serious offences have been held to be absolute offences, the court has taken into account no more than the wording of the Act and the character and seriousness of the mischief which constitutes the offence.
The choice would be much more difficult if there were no other way open than either mens rea in the full sense or an absolute offence; for there are many kinds of case where putting on the prosecutor the full burden of proving mens rea creates great difficulties and may lead to many unjust acquittals. But there are at least two other possibilities. Parliament has not infrequently transferred the onus as regards mens rea to the accused, so that, once the necessary facts are proved, he must convince the jury that on balance of probabilities he is innocent of any criminal intention. I find it a little surprising that more use has not been made of this method: but one of the bad effects of the decision of this House in Woolmington v. Director of Public Prosecutions
 AC 462
may have been to discourage its use. The other method would be in effect to substitute in appropriate classes of cases gross negligence for mens rea in the full sense as the mental element necessary to constitute the crime. It would often be much easier to infer that Parliament must have meant that gross negligence should be the necessary mental element than to infer that Parliament intended to create an absolute offence. A variant of this would be to accept the view of Cave J. in Reg. v. Tolson(1889) 23 Q.B.D. 168, 181. This appears to have been done in Australia where authority appears to support what Dixon J. said in Proudman v. Dayman(1941) 67 C.L.R. 536, 540:
“As a general rule an honest and reasonable belief in a state of facts which, if they existed, would make the defendant's act innocent affords an excuse for doing what would otherwise be an offence.”
It may be that none of these methods is wholly satisfactory but at least the public scandal of convicting on a serious charge persons who are in no way blameworthy would be avoided.
If this section means what the Divisional Court have held that it means, then hundreds of thousands of people who sublet part of their premises or take in lodgers or are concerned in the management of residential premises or institutions are daily incurring a risk of being convicted of a serious offence in circumstances where they are in no way to blame. For the greatest vigilance cannot prevent tenants, lodgers or inmates or guests whom they bring in from smoking cannabis cigarettes in their own rooms. It was suggested in argument that this appellant brought this conviction on herself because it is found as a fact that when the police searched the premises there were people there of the “beatnik fraternity.” But surely it would be going a very long way to say that persons managing premises of any kind ought to safeguard themselves by refusing accommodation to all who are of slovenly or exotic appearance, or who bring in guests of that kind. And unfortunately drug taking is by no means confined to those of unusual appearance.
Speaking from a rather long experience of membership of both Houses, I assert with confidence that no Parliament within my recollection would have agreed to make on offence of this kind an absolute offence if the matter had been fully explained to it. So, if the court ought only to hold an offence to be an absolute offence where it appears that that must have been the intention of Parliament, offences of this kind are very far removed from those which it is proper to hold to be absolute offences.
I must now turn to the question what is the true meaning of section 5 of the 1965 Act. It provides:
“If a person — (
a) being the occupier of any premises, permits those premises to be used for the purpose of smoking cannabis or cannabis resin or of dealing in cannabis or cannabis resin (whether by sale or otherwise); or (
b) is concerned in the management of any premises used for any such purpose as aforesaid; he shall be guilty of an offence against this Act.”
We are particularly concerned with paragraph (
b), and the first question is what is meant by “used for any such purpose.” Is the “purpose” the purpose of the smoker or the purpose of the management? When in Warner's case
 2 A.C. 256, 277 I dealt briefly with Yeandel's case
 1 Q.B. 440, I thought it was the purpose of the smoker, but fuller argument in the present case brought out that an identical provision occurs in section 8 (
d) which deals with opium. This latter provision has been carried on from the Dangerous Drugs Act, 1920, and has obviously been copied into the later legislation relating to cannabis. It would require strong reasons — and there are none — to justify giving this provision a new meaning in section 5 different from that which it had in the 1920 Act and now has in section 8 of the 1965 Act. I think that in section 8 it is clear that the purpose is the purpose of the management. The first purpose mentioned is the purpose of the preparation of opium for smoking which can only be a purpose of the management. I believe that opium cannot be smoked casually anywhere at any time as can a cannabis cigarette. The section is dealing with “opium dens” and the like when the use of opium is the main purpose for which the premises are used. But it is a somewhat strained use of language to say that an ordinary room in a house is “used for the purpose” of smoking cannabis when all that happens is that some visitor lights a cannabis cigarette there. Looking to the origin and context of this provision, I have come to the conclusion that it cannot be given this wide meaning. No doubt this greatly reduces the scope of this provision when applied to the use of cannabis. But that is apt to happen when a draftsman simply copies an existing provision without regard to the different circumstances in which it is to operate. So, if the purpose is the purpose of the management, the question whether the offence with regard to opium in 1920, and now with regard to cannabis, is absolute can hardly arise. It could only arise if, although the manager not only knew about cannabis smoking and conducted the premises for that purpose, some person concerned in the management had no knowledge of that. One would first have to decide whether a person who is not actually assisting in the management can be regarded as being “concerned in the management,” although ignorant of the purpose for which the manager was using the premises. Even if such a person could be regarded as “concerned in the management,” I am of opinion that, for the reasons which I have given, he could not be convicted without proof of mens rea.
I would allow the appeal and quash the appellant's conviction.
LORD MORRIS OF BORTH-Y-GEST. My Lords, it has frequently been affirmed and should unhesitatingly be recognised that it is a cardinal principle of our law that mens rea, an evil intention or a knowledge of the wrongfulness of the act, is in all ordinary cases an essential ingredient of guilt of a criminal offence. It follows from this that there will not be guilt of an offence created by statute unless there is mens rea or unless Parliament has by the statute enacted that guilt may be established in cases where there is no mens rea.
To this effect were the words of Wright J. in Sherras v. De Rutzen
 1 Q.B. 918 and in Derbyshire v. Houliston in
 1 Q.B. 772. In the judgment of the Privy Council in Lim Chin Aik v. The Queen
 A.C. 160 the principle was amply expressed. It was said, at p. 172: “That proof of the existence of a guilty intent is an essential ingredient of a crime at common law is not at all in doubt.”
But as Parliament is supreme it is open to Parliament to legislate in such a way that an offence may be created of which someone may be found guilty though mens rea is lacking. There may be cases in which, as Channell J. said in Pearks, Gunston & Tee Ltd. v. Ward
 2 K.B. 1, 11:
“… the Legislature has thought it so important to prevent the particular act from being committed that it absolutely forbids it to be done; and if it is done the offender is liable to a penalty whether he had any mens rea or not, and whether or not he intended to commit a breach of the law.”
Thus in diverse situations and circumstances and for any one of a variety of reasons Parliament may see fit to create offences and make people responsible before criminal courts although there is an absence of mens rea. But I would again quote with appreciation (as I did in Warner's case,
 2 A.C. 256) the words of Lord Goddard C.J., in Brend v. Wood(1946) 175 L.T. 306, 307, when he said:
“It is of the utmost importance for the protection of the liberty of the subject that a court should always bear in mind that, unless a statute, either clearly or by necessary implication, rules out mens rea as a constituent part of a crime, the court should not find a man guilty of an offence against the criminal law unless he has a guilty mind.”
The intention of Parliament is expressed in the words of an enactment. The words must be looked at in order to see whether either expressly or by necessary implication they displace the general rule or presumption that mens rea is a necessary prerequisite before guilt of an offence can be found. Particular words in a statute must be considered in their setting in the statute and having regard to all the provisions of the statute and to its declared or obvious purpose. In 1842 in Attorney-General v. Lockwood(1842) 9 M. & W. 378, 398 Alderson B. said:
“The rule of law, I take it, upon the construction of all statutes … is, whether they be penal or remedial, to construe them according to the plain, literal, and grammatical meaning of the words in which they are expressed, unless that construction leads to a plain and clear contradiction of the apparent purpose of the Act, or to some palpable and evident absurdity.”
It must be considered, therefore, whether by the words of a penal statute it is either express or implied that there may be a conviction without mens rea or, in other words, whether what is called an absolute offence is created.
In Dyke v. Elliott. The “Gauntlet”(1872) L.R. 4 P.C. 184, 191 it was said:
“No doubt all penal statutes are to be construed strictly, that is to say, the court must see that the thing charged as an offence is within the plain meaning of the words used, and must not strain the words on any notion that there has been a slip, that there has been a casus omissus, that the thing is so clearly within the mischief that it must have been intended to be included and would have been included if thought of. On the other hand, the person charged has a right to say that the thing charged, although within the words, is not within the spirit of the enactment. But where the thing is brought within the words and within the spirit, there a penal enactment is to be construed, like any other instrument, according to the fair common-sense meaning of the language used, and the court is not to find or make any doubt or ambiguity in the language of a penal statute, where such doubt or ambiguity would clearly not be found or made in the same language in any other instrument.”
The inquiry must be made, therefore, whether Parliament has used words which expressly enact or impliedly involve that an absolute offence is created. Though sometimes help in construction is derived from noting the presence or the absence of the word “knowingly,” no conclusive test can be laid down as a guide in finding the fair, reasonable and common-sense meaning of language But in considering whether Parliament has decided to displace what is a general and somewhat fundamental rule it would not be reasonable lightly to impute to Parliament an intention to create an offence in such a way that someone could be convicted of it who by all reasonable and sensible standards is without fault.
There have been many cases in recent periods in which in reference to a variety of different statutory enactments questions have been raised whether absolute offences have been created. Some of these cases illustrate the difficulties that are created if Parliament uses language or phrases as to the meaning of which legitimate differences of opinion can arise. I do not propose to recite or survey these cases because, in my view, the principles which should guide construction are clear and, save to the extent that principles are laid down, the cases merely possess the interest which is yielded by seeing how different questions have, whether correctly or incorrectly, been decided in reference to varying sets of words in various different statutes.
The question must always be — what has Parliament enacted? That is the question in the present case and to that I now turn. The wording of section 5 of the Dangerous Drugs Act, 1965, is as follows:
“If a person — (
a) being the occupier of any premises, permits those premises to be used for the purpose of smoking cannabis or cannabis resin or of dealing in cannabis or cannabis resin (whether by sale or otherwise); or (
b) is concerned in the management of any premises used for any such purpose as aforesaid; he shall be guilty of an offence against this Act.”
The words are nearly the same as and presumably were derived from words in section 5 of the Dangerous Drugs Act, 1920, concerning opium.
In the present case the appellant was charged with being concerned in the management of certain premises situate at Fries Farm which were used for the purpose of smoking cannabis or cannabis resin. I need not recite the facts which are set out in the case stated.
It was for the prosecution to prove the guilt of the appellant. It was found by the magistrates that the appellant had no knowledge whatsoever that cannabis had been smoked in the house. The prosecution contended that guilt can be established of the offence created by section 5 (
b) if a person is concerned in the management of premises in which cannabis is in fact smoked. The consequence was acknowledged and indeed asserted that if some persons managed a hostel containing, say, 50 to 100 rooms, and if on one day in one room an occupant smoked one cannabis cigarette without the knowledge of the persons managing, they would have no defence to a charge under section 5 (
b). If Parliament has so enacted, then the law must be enforced. But I am sure that that is not what Parliament has decreed.
If someone is concerned in management there must at least be knowledge of what it is that is being managed: otherwise there could be no concern in it. If someone is concerned in the management of a building containing a number of separately let residential flats the concern in such case would be in the arrangements for the lettings and in the arrangements relating to lifts or staircases or the structure of the building as a whole. The concern would be in the management of premises used for residential purposes. In the ordinary course of things the landlord or the manager would have no right of entry into a flat and would have no concern with any normal, reasonable and lawful activity within a flat. If a tenant, who was a nonsmoker, had a guest one day who smoked a pipe of tobacco in the flat, it would be a strained and unnatural use of language to describe the flat which the tenant rented as being premises used for the purpose of smoking. It would be equally strained and unnatural to describe the landlord or his agent as being concerned in the management of premises used for the purpose of smoking. If on an isolated occasion a tenant gave a showing of some cinematograph films to his friends, it would be unreasonable to describe the manager of the flats (who had no occasion to know of the film showing) as being one who was concerned in the management of premises used for the purpose of exhibiting films.
If a tenant took sugar with his tea it would be fanciful to describe the flat as premises used for the purpose of putting sugar into tea.
It seems to me, therefore, that the words “premises … used for the purpose of smoking cannabis” are not happily chosen if they were intended to denote premises in which at any time cannabis is smoked. In my opinion, the words “premises … used for the purpose of …” denote a purpose which is other than quite incidental or casual or fortuitous: they denote a purpose which is or has become either a significant one or a recognised one though certainly not necessarily an only one. There is no difficulty in appreciating what is meant if it is said that premises are used for the purposes of a dance hall or a billiard hall or a bowling alley or a hairdressing saloon or a café. A new or additional use might, however, arise. It might happen that a house let as a private dwelling might come to be used as a brothel or for the purposes of prostitution. A room let for private occupation might come to be the resort of a number of people who wished to smoke opium so that the time would come when the room could rationally be described as a room used for the purpose of smoking opium.
The words “concerned in the management of any premises used for the purpose of” are, in my view, to be considered together and as one phrase. Even so the phrase may be capable of two meanings. It could denote the management of premises used for a certain purpose in the sense that the management is limited to management in respect of the premises themselves. It could denote the management of premises used for a certain purpose in the sense that the management was concerned either additionally or perhaps separately with the purpose for which the premises were used. Thus, if someone is said so to be concerned in the management of premises used for the purpose of dancing, he could be someone concerned only in the management of the premises themselves, or he could be someone who additionally or possibly separately was concerned with the dancing. On either approach and with an ordinary use of words, it would seem to me that the person would be one who would have and would need to have knowledge of the use of the premises for the particular purpose.
It is said that the intention of Parliament was to impose a duty on all persons concerned in the management of any premises to exercise vigilance to prevent the smoking of cannabis. If that had been the intention of Parliament different words would have been used. It would be possible for Parliament to enact, though it would be surprising if it did, that if anyone should at any time smoke cannabis on any premises, then all those concerned in the management of those premises, whether they knew of the smoking or not, should automatically be guilty of a criminal offence. Yet this is in effect what it is now said that Parliament has enacted. The implications are astonishing. Parliament would not only be indirectly imposing a duty upon persons concerned in the management of any premises requiring them to exercise complete supervision over all persons who enter the premises to ensure that no one of them should smoke cannabis, but Parliament would be enacting that the persons concerned in the management would become guilty of an offence if, unknown to them, someone by surreptitiously smoking cannabis eluded the most elaborately devised measures of supervision. There would not be guilt by reason of anything done nor even by reasons of any carelessness, but by reason of the unknown act of some unknown person whom it had not been found possible to control. When the range of possible punishments is remembered the unlikelihood that Parliament intended to legislate in such way becomes additionally apparent.
For the reasons that I have indicated I consider that on a fair reading of the phrase “concerned in the management of premises used for the purpose of” a link is denoted between management and user for a purpose. To say that someone is concerned in the management of premises used for the purpose of smoking cannabis involves, in my view, that his management is with knowledge that the premises are so used. The wording of section 5 (
b) contains positive indications that mens rea is an essential ingredient of an offence. Even if, contrary to my view, it is not affirmatively enacted that there must be mens rea I cannot read the wording as enacting that there need not be mens rea. I find it wholly impossible to say that the statute has either clearly, or by necessary implication, ruled out mens rea as a constituent part of guilt.
On the findings of the magistrates it follows that the appellant was not guilty. I would, therefore, allow the appeal. Accordingly, in my view, the case should be remitted to the Divisional Court with a direction to quash the conviction.
LORD PEARCE. My Lords, the prosecution contend that any person who is concerned in the management of premises where cannabis is in fact smoked even once, is liable, though he had no knowledge and no guilty mind. This is, they argue, a practical act intended to prevent a practical evil. Only by convicting some innocents along with the guilty can sufficient pressure be put upon those who make their living by being concerned in the management of premises. Only thus can they be made alert to prevent cannabis being smoked there. And if the prosecution have to prove knowledge or mens rea, many prosecutions will fail and many of the guilty will escape. I find that argument wholly unacceptable.
The notion that some guilty mind is a constituent part of crime and punishment goes back far beyond our common law. And at common law mens rea is a necessary element in a crime. Since the Industrial Revolution the increasing complexity of life called into being new duties and crimes which took no account of intent. Those who undertake various industrial and other activities, especially where these affect the life and health of the citizen, may find themselves liable to statutory punishment regardless of knowledge or intent, both in respect of their own acts or neglect and those of their servants. But one must remember that normally mens rea is still an ingredient of any offence. Before the court will dispense with the necessity for mens rea it has to be satisfied that Parliament so intended. The mere absence of the word “knowingly” is not enough. But the nature of the crime, the punishment, the absence of social obloquy, the particular mischief and the field of activity in which it occurs, and the wording of the particular section and its context, may show that Parliament intended that the act should be prevented by punishment regardless of intent or knowledge.
Viewing the matter on these principles, it is not possible to accept the prosecution's contention. Even granted that this were in the public health class of case, such as, for instance, are offences created to ensure that food shall be clean, it would be quite unreasonable. It is one thing to make a man absolutely responsible for all his own acts and even vicariously liable for his servants if he engages in a certain type of activity. But it is quite another matter to make him liable for persons over whom he has no control. The innocent hotel-keeper, the lady who keeps lodgings or takes paying guests, the manager of a cinema, the warden of a hostel, the matron of a hospital, the house-master and matron of a boarding school, all these, it is conceded, are, on the prosecution's argument, liable to conviction the moment that irresponsible occupants smoke cannabis cigarettes. And for what purpose is this harsh imposition laid on their backs? No vigilance by night or day can make them safe. The most that vigilance can attain is advance knowledge of their own guilt. If a smell of cannabis comes from a sitting-room, they know that they have committed the offence. Should they then go at once to the police and confess their guilt in the hope that they will not be prosecuted? They may think it easier to conceal the matter in the hope that it may never be found out. For if, though morally innocent, they are prosecuted they may lose their livelihood, since thereafter, even though not punished, they are objects of suspicion. I see no real, useful object achieved by such hardship to the innocent. And so wide a possibility of injustice to the innocent could not be justified by any benefit achieved in the determent and punishment of the guilty. If, therefore, the words creating the offence are as wide in their application as the prosecution contend, Parliament cannot have intended an offence to which absence of knowledge or mens rea is no defence.
Parliament might, of course, have taken what was conceded in argument to be a fair and sensible course. It could have said, in appropriate words, that a person is to be liable unless he proves that he had no knowledge or guilty mind. Admittedly, if the prosecution have to prove a defendant's knowledge beyond reasonable doubt, it may be easy for the guilty to escape. But it would be very much harder for the guilty to escape if the burden of disproving mens rea or knowledge is thrown on the defendant. And if that were done, innocent people could satisfy a jury of their innocence on a balance of probabilities. It has been said that a jury might be confused by the different nature of the onus of satisfying “beyond reasonable doubt” which the prosecution have to discharge and the onus “on a balance of probabilities” which lies on a defendant in proving that he had no knowledge or guilt. I do not believe that this would be so in this kind of case. Most people can easily understand rules that express in greater detail that which their own hearts and minds already feel to be fair and sensible. What they find hard to understand is rules that go “against the grain” of their own common sense. If a judge on a drug case, feeling disheartened, perhaps, after a close study of Warner's case
 2 A.C. 256, had given the jury no direction as to the law, and had simply said that they must consider the facts and do their best with the charge, I believe that they would evolve their duty in some such form as this; “First, I suppose, we must make
sure that there really was drug smoking on the premises” (or “that he really
had drugs on him” or whatever the charge may be) “and then it is up to the defendant to persuade us that he did not know, or was not guilty for some other good reason.” If I am right in this surmise, any judicial elaboration of their own instinctive reactions would be quite easy for them to understand.
If it were possible in some so-called absolute offences to take this sensible half-way house, I think that the courts should do so. This has been referred to in Warner's case
 2 A.C. 256. I see no difficulty in it apart from the opinion of Viscount Sankey L.C. in Woolmington v. Director of Public Prosecutions
 AC 462
. But so long as the full width of that opinion is maintained, I see difficulty. There are many cases where the width of that opinion has caused awkward problems. But before reducing that width your Lordships would obviously have to consider all the aspects of so far-reaching a problem. In the present case Miss Heilbron was wisely loth to involve herself in this when she had easier and surer paths to pursue.
The Australian High Court, founding on Cave J. (1889) 23 Q.B.D. 168, 181, and Wills J. (at p. 175) in Reg. v. Tolson have evolved a defence of reasonable mistake of fact, and the burden of proving this on a balance of probabilities rests upon the defendant. The whole matter is discussed in an interesting article, “Strict Responsibility in the High Court of Australia,” by Professor Colin Howard in the Law Quarterly Review (1960) vol. 76 p. 547. He concludes at p. 566:
“Where a statutory prohibition is cast in terms which at first sight appear to impose strict responsibility, they should be understood merely as imposing responsibility for negligence but emphasising that the burden of rebutting negligence by affirmative proof of reasonable mistake rests upon the defendant.” He cites Maher v. Musson(1934) 52 C.L.R. 100
per Dixon J., at p. 105, and
per Evatt and McTiernan JJ. at p. 108; cf. Sherras v. De Rutzen
 1 Q.B. 918, 921
per Day J.
That decision was before Woolmington's case
 AC 462
. In Thomas v. The King(1937) 59 C.L.R. 279 the matter was further discussed, but I see no reference to Woolmington's case
 AC 462
. I should be happy to be persuaded either that it does not prevent us from adopting such a satisfactory concept as the Australian courts have evolved or that its wide effect should be limited. But it has not been necessary for the purposes of the present case to go fully into that aspect of the matter.
Although the subsection cannot constitute an absolute offence in the wide application for which the prosecution contend, it does not follow that on a narrower construction it may not constitute an absolute offence. By the term “absolute” I mean an offence to which the normal assumption of mens rea does not apply, but in which the actual words of the offence (without any additional implication of mens rea) may well import some degree of knowledge, as, for example, the word “possession” as in Warner's case
 2 A.C. 256. In saying that the section relating to possession (which was there under discussion) was absolute, I was using it (as the context was intended to show) in that loose and convenient sense which had been used in the argument.
The history of the subsection and the words themselves lend strong support to the view that a narrow meaning was intended. In the Dangerous Drugs Act, 1920, section 4 (c) and (d), identical words are used save that the “purpose” there was “the preparation of opium for smoking or the sale or smoking of prepared opium” instead of “the purpose of smoking cannabis or cannabis resin or of dealing in cannabis or cannabis resin whether by sale or otherwise.” Section 4 of the 1920 Act was in fact re-enacted in section 8 of the 1965 Act now under consideration. The words thus taken from the 1920 Act cannot have a different sense when used in the 1965 Act, especially when they are re-enacted in another part of the 1965 Act itself. Any guide provided by their context in 1920 can, therefore, be useful in deciding their meaning in 1965, when applied to cannabis smoking. The prosecution point out that opium smoking needs more paraphernalia and preparation (in what are sometimes called “opium dens”) and that considerations applicable to them are out of place in dealing with cannabis, which may be smoked casually and without preparation. Anyone may carry a cannabis cigarette and light it in the normal places and in normal circumstances of life. But that very fact makes it the more unlikely that responsibility for such casual acts of invitees or licensees should fall on those who manage premises unless they are managing them for just such a purpose.
The whole context and content of the original section 5 of the 1920 Act show that it was considering premises one of whose “purposes” was opium smoking. The “purpose” there referred to is thus the purpose of the management or a purpose known to or acquiesced in by them. I think that the words which were lifted from that section and enacted in relation to cannabis in section 5 of the Dangerous Drugs Act, 1965, must be given a similar narrow construction. There was no need to insert the word “purpose,” if all that was intended was premises where cannabis is in fact smoked. Being concerned in the management of premises used for the purpose of smoking cannabis necessarily imports some knowledge of the use of the premises for the purpose. Admittedly Miss Sweet had no knowledge.
I appreciate that this limitation will, as the prosecution contend, rob the section of much of its force. If a wider application or efficiency were desired it could be achieved by a change of onus and a consideration of what exactly is being required of landladies and the like. They cannot reasonably be branded with guilt whenever there happens to be on their premises someone who without their knowledge or assent smokes cannabis.
I would allow the appeal.
LORD WILBERFORCE. My Lords, in my opinion Miss Stephanie Sweet, who was found to have “no knowledge whatever that [her] house was being used for the purpose of smoking cannabis,” ought not to have been convicted.
Her conviction was based upon section 5 (
b) of the Dangerous Drugs Act, 1965, and upon an interpretation of the words “concerned in the management of any premises used [for the purpose of smoking cannabis or cannabis resin or of dealing in cannabis or cannabis resin]” which makes a person liable to prosecution who lets, or licenses the occupation of premises, upon which cannabis or cannabis resin is smoked or dealt in. It requires no amplification to show how wide a category of persons would thus be brought into the category of potential offenders. So, for this appeal, the essential question is to determine whether this interpretation is correct.
The words “concerned in the management” are not, on the face of them, very clear, but at least they suggest some technical or acquired meaning, some meaning other than one which refers merely to such common transactions as letting or licensing the occupation of premises. For if it had been intended to penalise anyone who lets or licenses premises on which cannabis comes to be smoked, it would have been easy to do so in simple language. This impression is strengthened when the following words of the subsection are read. They reflect what I would think to be logically correct — namely, that one does not “manage” premises, the inert subject of a conveyance or a lease, but rather some human activity on the premises which the manager has an interest in directing. And so, when the subsection speaks of management of premises, and for a purpose, I would expect the purpose for which the premises are used to be that of the manager: otherwise, what would be the nature and object of the management?
A consideration of previous and analogous legislation removes any doubt that these words are intended to refer to such a special and limited class as I have described, one which quite clearly excludes such persons as Miss Sweet. This legislation deals with other “anti-social” activities such as the keeping of brothels, opium “dens” and gaming houses.
1. The Criminal Law Amendment Act, 1885, section 13, dealt with the keeping of brothels. It penalised a person who “keeps or manages or acts or assists in the management of a brothel.” It dealt also with persons, other than managers, tenants, occupiers, lessors and (by an amendment in 1912) persons in charge, but in relation to them it stated explicity the requirement of knowledge — “knowingly permits,” “lets with knowledge,” “is wilfully party to the continued use.” These fit in with and emphasise the conception of purposeful management. Substantially similar language is taken into the modern Sexual offences Act, 1956, which refers to managing or acting or assisting in management. It is perhaps worth observation that this Act refers both to “used as a brothel” and “used for the purposes of habitual prostitution,” showing that when a convenient noun exists which includes the concept of a prohibited purpose, it is adopted, and that “used for the purposes” is employed to denote a similar type of situation as to which no convenient noun can be found or coined.
2. The Dangerous Drugs Act, 1921, dealt with opium. The relevant sections are reproduced in the Act of 1965 (section 8), and it is obvious that the provisions regarding cannabis are based upon them. In dealing with management of premises it seems clear enough that what is in mind is not the lessor of premises on which opium may come to be smoked, but a manager of what, if a noun is required, might be called “opium dens.” No doubt opium smoking is a more elaborate and prolonged process than smoking of cannabis, so that the transference of legislation from one activity to the other is not completely appropriate, but the difference (perhaps not understood by the draftsman) is not sufficient to impel us to a fresh conception of management.
3. The use of the word “management” in relation to gaming houses goes back at least to the Gaming Act, 1845 (section 4). The expression “concerned in the management” is used in section 5. The Betting Act, 1853 (section 3), combines prohibition of “permitting” by occupiers with prohibition of management of a house or place used for the purposes of betting, a comparable structure to that of section 5 of the Dangerous Drugs Act, 1965. I need not trace this wording through the mountains of later enactments.
I am left with no doubt after examination of this legislation that when the Dangerous Drugs Act, 1964 (the predecessor of that of 1965), adopted in relation to cannabis language which penalised, on the one hand, “permitting to be used” and, on the other hand, being “concerned in the management of premises used for the purposes …” it must, in the latter provision, have had in mind the same kind of purposeful management activity as was referred to, in analogous connections, in previous legislation. One can describe what is penalised as being concerned in the management of a cannabis shop, or a cannabis smoking den or parlour, a type of activity which no doubt includes not only one where this was the direct or main purpose of the manager, or person concerned in the management, but also cases where, by extension or infiltration and acquiescence this purpose had come to be included in the purposes for which the premises are being managed or, one might say, run.
If this is the correct meaning to extract from the language, when one considers that there is also a wide area of penalisation elsewhere of possession and of permitting by occupiers, there is a rational statutory scheme of considerable scope. I see no reason to strain the language of section 5 (
b) so as to convert it into, in effect, an instrument of amateur law enforcement which may catch many innocent persons: whether the section, as so interpreted, is too severe or not severe enough, is something for Parliament to consider.
On this admittedly prosaic interpretation of the subsection, I do not embark upon a wider examination of the problem of absolute offences, or of guilty intention. As in Warner's case
 2 A.C. 256, the word “possession” carried its own content of mental intention so, perhaps a fortiori, do the words “concerned in the management of premises used for the purpose …” and there is no occasion to look beyond them for some separate ingredient which might, in fact, be difficult to define.
I would allow the appeal.
LORD DIPLOCK. My Lords, on premises of which Miss Sweet was the occupier but from which she was frequently absent cannabis was smoked without her permission or knowledge. She was charged before the Woodstock magistrates with an offence under section 5 of the Dangerous Drugs Act, 1965. She was not charged under paragraph (
a) as an occupier of premises who “permits those premises to be used for the purpose of smoking cannabis” but under paragraph (
b) as a person “concerned in the management of … premises used for that purpose.” She was convicted and fined £25.
That conviction was upheld by the Divisional Court who gave leave to appeal to your Lordships' house and certified that the following points of law of general public importance are involved in their decision, namely:
“(1) Whether section 5 (
b) of the Dangerous Drugs Act, 1965, creates an absolute offence. (2) What, if any, mental element is involved in the offence; and (since leave to appeal is given in regard to (1) and (2) above) (3) Whether on the facts found a reasonable bench of magistrates, properly directing their minds as to the law, could have convicted the appellant.”
The expression “absolute offence” used in the first question is an imprecise phrase currently used to describe an act for which the doer is subject to criminal sanctions even though when he did it he had no mens rea, but mens rea itself also lacks precision and calls for closer analysis than is involved in its mere translation into English by Wright J. in Sherras v. de Rutzen
 1 Q.B. 918, 921 as “evil intention or a knowledge of the wrongfulness of the act” — a definition which suggests a single mental element common to all criminal offences and appears to omit thoughtlessness which, at any rate if it amounted to a reckless disregard of the nature or consequences of an act, was a sufficient mental element in some offences at common law.
A more helpful exposition of the nature of mens rea in both common law and statutory offences is to be found in the judgment of Stephen J. in Reg. v. Tolson(1889) 23 Q.B.D. 168, 187. He said:
“The full definition of every crime contains expressly or by implication a proposition as to a state of mind. Therefore, if the mental element of any conduct alleged to be a crime is proved to have been absent in any given case, the crime so defined is not committed; or, again, if a crime if fully defined, nothing amounts to that crime which does not satisfy that definition.”
Where the crime consists of doing an act which is prohibited by statute the proposition as to the state of mind of the doer which is contained in the full definition of the crime must be ascertained from the words and subject-matter of the statute. The proposition, as Stephen J. pointed out, may be stated explicitly by the use of such qualifying adverbs as “maliciously,” “fraudulently,” “negligently” or “knowingly” — expressions which in relation to different kinds of conduct may call for judicial exegesis. And even without such adverbs the words descriptive of the prohibited act may themselves connote the presence of a particular mental element. Thus, where the prohibited conduct consists in permitting a particular thing to be done the word “permit” connotes at least knowledge or reasonable grounds for suspicion on the part of the permittor that the thing will be done and an unwillingness to use means available to him to prevent it and, to take a recent example, to have in one's “possession” a prohibited substance connotes some degree of awareness of that which was within the possessor's physical control: Reg. v. Warner
 2 A.C. 256.
But only too frequently the actual words used by Parliament to define the prohibited conduct are in themselves descriptive only of a physical act and bear no connotation as to any particular state of mind on the part of the person who does the act. Nevertheless, the mere fact that Parliament has made the conduct a criminal offence gives rise to some implication about the mental element of the conduct proscribed. It has, for instance, never been doubted since M'Naghten's Case (1843) 10 Cl. & F. 200, that one implication as to the mental element in any statutory offence is that the doer of the prohibited act should be sane within the M'Naghten rules; yet this part of the full definition of the offence is invariably left unexpressed by Parliament. Stephen J. in Reg. v. Tolson(1889) 23 Q.B.D. 168 suggested other circumstances never expressly dealt with in the statute where a mental element to be implied from the mere fact that the doing of an act was made a criminal offence would be absent, such as where it was done in a state of somnambulism or under duress, to which one might add inevitable accident. But the importance of the actual decision of the nine judges who constituted the majority in Reg. v. Tolson, which concerned a charge of bigamy under section 57 of the Offences Against the Person Act, 1861, was that it laid down as a general principle of construction of any enactment, which creates a criminal offence, that, even where the words used to describe the prohibited conduct would not in any other context connote the necessity for any particular mental element, they are nevertheless to be read as subject to the implication that a necessary element in the offence is the absence of a belief, held honestly and upon reasonable grounds, in the existence of facts which, if true, would make the act innocent. As was said by the Privy Council in Bank of New South Wales v. Piper
 AC 383
, 389, 390, the absence of mens rea really consists in such a belief by the accused.
This implication stems from the principle that it is contrary to a rational and civilised criminal code, such as Parliament must be presumed to have intended, to penalise one who has performed his duty as a citizen to ascertain what acts are prohibited by law (ignorantia juris non excusat) and has taken all proper care to inform himself of any facts which would make his conduct lawful.
Where penal provisions are of general application to the conduct of ordinary citizens in the course of their every day life the presumption is that the standard of care required of them in informing themselves of facts which would make their conduct unlawful, is that of the familiar common law duty of care. But where the subject-matter of a statute is the regulation of a particular activity involving potential danger to public health, safety or morals in which citizens have a choice as to whether they participate or not, the court may feel driven to infer an intention of Parliament to impose by penal sanctions a higher duty of care on those who choose to participate and to place upon them an obligation to take whatever measures may be necessary to prevent the prohibited act, without regard to those considerations of cost or business practicability which play a part in the determination of what would be required of them in order to fulfil the ordinary common law duty of care. But such an inference is not lightly to be drawn, nor is there any room for it unless there is something that the person on whom the obligation is imposed can do directly or indirectly, by supervision or inspection, by improvement of his business methods or by exhorting those whom he may be expected to influence or control, which will promote the observance of the obligation (see Lim Chin Aik v. The Queen
 A.C. 160, 174).
The numerous decisions in the English courts since Reg. v. Tolson(1889) 23 Q.B.D. 168 in which this later inference has been drawn rightly or, as I think, often wrongly are not easy to reconcile with others where the court has failed to draw the inference, nor are they always limited to penal provisions designed to regulate the conduct of persons who choose to participate in a particular activity as distinct from those of general application to the conduct of ordinary citizens in the course of their every day life. It may well be that had the significance of Reg. v. Tolson been appreciated here, as it was in the High Court of Australia, our courts, too, would have been less ready to infer an intention of Parliament to create offences for which honest and reasonable mistake was no excuse.
Its importance as a guide to the construction of penal provisions in statutes of general application was recognised by Dixon J. in Maher v. Musson(1934) 52 C.L.R. 100, 104, and by the majority of the High Court of Australia in Thomas v. The King(1937) 59 C.L.R. 279. It is now regularly adopted in Australia as a general principle of construction of statutory provisions of this kind.
By contrast, in England the principle laid down in Reg. v. Tolson(1889) 23 Q.B.D. 168 has been overlooked until recently (see Reg. v. Gould
 2 QB 65
) partly because the ratio decidendi was misunderstood by the Court of Criminal Appeal in Rex v. Wheat, Rex v. Stocks
 2 K.B. 119 and partly, I suspect, because the reference in Reg. v. Tolson(1889) 23 Q.B.D. 168 to the mistaken belief as being a “defence” to the charge of bigamy was thought to run counter to the decision of your Lordships' House in Woolmington v. Director of Public Prosecutions
 AC 462
. That expression might have to be expanded in the light of what was said in Woolmington's case, though I doubt whether a jury would find the expansion much more informative than describing the existence of the mistaken belief as a defence to which they should give effect unless they felt sure either that the accused did not honestly hold it or, if he did, that he had no reasonable grounds for doing so.
Woolmington's case affirmed the principle that the onus lies upon the prosecution in a criminal trial to prove all the elements of the offence with which the accused is charged. It does not purport to lay down how that onus can be discharged as respects any particular elements of the offence. This, under our system of criminal procedure, is left to the common sense of the jury. Woolmington's case did not decide anything so irrational as that the prosecution must call evidence to prove the absence of any mistaken belief by the accused in the existence of facts which, if true, would make the act innocent, any more than it decided that the prosecution must call evidence to prove the absence of any claim of right in a charge of larceny. The jury is entitled to presume that the accused acted with knowledge of the facts, unless there is some evidence to the contrary originating from the accused who alone can know on what belief he acted and on what ground the belief, if mistaken, was held. What Woolmington's case did decide is that where there is any such evidence the jury after considering it and also any relevant evidence called by the prosecution on the issue of the existence of the alleged mistaken belief should acquit the accused unless they feel sure that he did not hold the belief or that there were no reasonable grounds upon which he could have done so.
This, as I understand it, is the approach of Dixon J. to the onus of proof of honest and reasonable mistaken belief as he expressed it in Proudman v. Dayman(1941) 67 C.L.R. 536, 541. Unlike the position where a statute expressly places the onus of proving lack of guilty knowledge on the accused, the accused does not have to prove the existence of mistaken belief on the balance of probabilities; he has to raise a reasonable doubt as to its non-existence.
It has been objected that the requirement laid down in Reg. v. Tolson(1889) 23 Q.B.D. 168 and the Bank of New South Wales v. Piper
 AC 383
that the mistaken belief should be based on reasonable grounds introduces an objective mental element into mens rea. This may be so, but there is nothing novel in this. The test of the mental element of provocation which distinguishes manslaughter from murder has always been at common law and now is by statute the objective one of the way in which a reasonable man would react to provocation. There is nothing unreasonable in requiring a citizen to take reasonable care to ascertain the facts relevant to his avoiding doing a prohibited act.
It is, then, with these principles in mind that I approach the construction of section 5 of the Dangerous Drugs Act, 1965, under which Miss Sweet was charged. It contains separate prohibitions in paragraphs (
a) and (
b) respectively. The offence under (
a), with which Miss Sweet was not charged, can only be committed by the occupier of premises. The act of the occupier which is prohibited is to “permit” those premises to be used for the purpose of smoking cannabis or cannabis resin or of dealing in cannabis or cannabis resin. Here the word “permits,” used to define the prohibited act, in itself connotes as a mental element of the prohibited conduct knowledge or grounds for reasonable suspicion on the part of the occupier that the premises will be used by someone for that purpose and an unwillingness on his part to take means available to him to prevent it. As regards this offence there is no need to have recourse to the more general implication as to the need for mens rea where the words are in themselves descriptive only of a physical act.
In paragraph (
b) the phrase “concerned with the management of any premises,” unlike the phrase “being the occupier of any premises” in paragraph (
a), is not descriptive of a class of person to whom a particular kind of conduct subsequently defined is prohibited. It is part of the definition of the offence itself. The conduct prohibited is to be “concerned in the management of premises used for the purpose of smoking cannabis,” etc. What, if any, mental element does this compound phrase connote? The premises of which it is an offence to be concerned in the management are defined not by reference merely to what happens on them (e.g. “premises on which cannabis is smoked”) but by the purpose for which they are used. “Purpose” connotes an intention by some person to achieve a result desired by him. Whose purpose must it be that the premises should be used for smoking cannabis? The answer is, in my opinion, to be found in the words “is concerned in the management.” To manage or to be concerned in the management itself connotes control or direction of an activity to achieve a result desired by those who control or direct the activity. In my opinion, in the compound phrase “is concerned in the management of premises used for the purpose of smoking cannabis” etc., the purpose described must be the purpose of the person concerned in the management of the premises.
But at its highest against Miss Sweet the words of the paragraph are ambiguous as to whose is the relevant purpose. That ambiguity in a penal statute which, on the alternative construction that it would be sufficient if the purpose to use the premises for smoking cannabis were that of anyone who in fact smoked cannabis, would render her liable, despite lack of any knowledge or acquiescence on her part, should be unhesitatingly resolved in her favour.
In view of the finding that Miss Sweet “had no knowledge whatever that the house was being used for the purpose of smoking cannabis or cannabis resin” she could not properly be convicted of the offence charged. I, too, would allow this appeal.