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Principles - actus reus - the mental element

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Lord Diplock in Miller urged us to use 'conduct of the accused' rather than "actus reus"

The expression 'actus reus' is derived from Coke's Institutes "et actus non facit reum, nisi mens sit rea,"


By incorrectly using "reus" as an adjective instead of a noun, the phrase is likely to mislead, because it suggests that some positive act is required.  Whereas a failure or omission to act can give rise to criminal liability.


Bad Latin.

Lord Diplock said that it would be better that we avoid bad Latin and instead to think and speak about the conduct of the accused and his state of mind at the time of that conduct, instead of speaking of actus reus and mens rea.


Haughton v Smith [1975] HL

Lord Hailsham:

"Strictly speaking, though in almost universal use, it derives, I believe, from a mistranslation of the Latin aphorism: "Actus non facit reum nisi mens sit rea."

Properly translated, this means "An act does not make a man guilty of a crime, unless his mind be also guilty."

It is thus not the actus which is "reus," but the man and his mind respectively. Before the understanding of the Latin tongue has wholly died out of these islands, it is as well to record this as it has frequently led to confusion."

A useful translation is

 "an act does not make a person legally guilty unless the mind is legally blameworthy"


Contrasting judicial positions on the usefulness of using the terms actus reus  and mens rea.

Court of Appeal in Singh (Gurdev) v The Queen [1973] CA

Lord Lane:

"...the division of crimes into actus reus and mens rea is sometimes extremely helpful. In these particular circumstances it does nothing except cloud the issue."

Lynch v DPP for Northern Ireland [1975]

Simon of Glaisdale

"[The terms actus reus and mens rea] have, however, justified themselves by their usefulness; and I shall myself employ them in their traditional sensesónamely actus reus to mean such conduct as constitutes a crime if the mental element involved in the definition of the crime is also present (or, more shortly, conduct prohibited by law); and mens rea to mean such mental element, over and above volition, as is involved in the definition of the crime."

The mental element in actus reus

Actus reus, sometimes contains a mental element

  • In some assaults, foreseeing the risk of harm is a mental element.

  • Foreseeability is part of causation

  • Causation is part of the actus reus.

  • Therefore, the actus reus of some assaults requires a mental element to be proved by the prosecution.

"Actus non facit reum nisi mens sit rea"

actus = act

reum (reus) = liable

A man is not liable for his acts alone, but only if he acts with a guilty mind.

Examples of mental elements in actus reus

Actus reus of Theft Act offences includes "appropriation" and "possession", these require a mental element.

"Appropriation" and "possession" are recognised to be terms used in the actus reus of offences and yet necessarily involving some mental element in the accused.


Professor Glanville Williams has stated that some crimes, including attempts, were examples of crimes in which:

"The act constituting a crime may...take its criminal colouring entirely from the intent with which it is done."

The act "to take" or "to give" cannot be done by accident, yet are part of the actus reus.

There is a mental element implicit in the actus reus of any offence of unlawful possession.


Therefore the usual distinction between the mental element and the external manifestation of a crime can be difficult to apply in cases where the crime is one of 'possessing', 'permitting', 'keeping', 'appropriating', etc, because these terms simultaneously import both mental and physical elements.


D does not possess something, which, unknown to him, has become stuck to the sole of his shoe or the blade of his penknife Warner v Metropolitan Police Commissioner [1969] & Marriott [1971].  But, he may possess a controlled drug without realising what it is that he possesses. 


The correct legal concept of possession involves both the actus reus of possession and a state of mind, the animus possidendi, which can only be a part of the mens rea.


In practice, the animus possidendi is treated as if it were an element of the actus reus Animus possidendi must always be proved by the prosecution, whereas the burden of proof in respect of other mens rea elements is placed on the defence.

Causing an affray, that is causing terror to others by fighting, requires that the fighting be deliberate, and is part of the actus reus, Taylor v DPP [1973]

Thus, the Court of Appeal in R v Jones was content to define the actus reus of affray as "fighting or the show of force."

"Going equipped" (To have with one any instrument for use in a burglary, theft or cheat outside of one's place of abode). Section 25 of the Theft Act 1968.

The external conduct may be carrying a screwdriver.
If we ignore the question "What did D intend to use it for?" (that is his purpose) we are left with entirely innocent behaviour; carrying a screwdriver in the street.


The actus reus exists only if the purpose of an otherwise neutral object - the screwdriver - that the accused possesses is that he intends it to be used in for one of the criminal purposes mentioned.

"Carrying an offensive weapon in a public place" expresses the actus reus of section 1 (4), Prevention of Crimes Act 1953.

An offensive weapon turns on the accused's intention to injure another with it. It is this intention that translates an umbrella or hammer into an offensive weapon and hence allows us to describe the conduct as prohibited.


However, the actus reus is not holding an umbrella or hammer; it is carrying an offensive weapon R v Petrie [1961].

"Attempt" means D was trying to create the actus reus of the crime.

D is only is attempting to commit the crime (the actus reus of attempts) if his purpose is the attainment of that crime.

Sweet v Parsley [1970]

The ratio decidendi of Sweet v Parsley was not that an essential of liability, mens rea, was absent but that there was no actus reus.


What was prohibited was "running a cannabis den" and Miss Sweet was doing nothing of the sort.

  • One cannot "run" that of which one is ignorant.

  • The house was not "a cannabis den" that was not its function.

"Running" involved knowledge of the function given to the premises, this is part of the actus reus.

Lord Diplock said that the knowledge or purpose of the accused was a requisite of both parts of the actus reus - the "running" and what was "run".


Impersonation or "Personation" occurs by presenting oneself as another.

This offence can be committed by pretending to be a juryman, policeman, voter or many other persons.


The actus reus may be brought about accidentally or otherwise innocently.


Impersonation is the endeavour to appear as another. The crime of "impersonation" requires the deliberate pretence to be another, not merely causing another to mistake one for someone else   It does not dependent on convincing someone that one is the person one is pretending to be.

The actus reus of "impersonating a police officer," (section 52 (2), Police Act 1964), involves D having a particular purpose.


Rape "by inducing a married woman to have sexual intercourse by impersonating her husband" (section 1 (2) Sexual Offences Act 1956) involves the prohibited conduct of trying to appear as her husband.


Indecent assault only occurs when V has been sexually assaulted.

The crime occurs when there is an assault in "circumstances of indecency."


This indecency forms part of the actus reus of the offence in the same way that causing actual bodily harm is part of the actus reus of assault occasioning actual bodily harm.


"Circumstances of indecency" turn an assault into an indecent assault when D's purpose in the assault is a sexual purpose.


In R v Sutton, [1977] D photographed children in pornographic positions. He touched the children in order to arrange the poses. If his touching had been indecent (sexual) there would have been a sexual assault. But his intent was merely to arrange the subjects.


Only if the assault has sexual significance to the accused has the victim been indecently assaulted.


If one of the boys had thought the touching was sexual, he would have misunderstood the situation: he would not have been touched sexually "by accident."


The sexuality is part of the actus reus, not merely ulterior intent, as the crime refers to a distinct kind of assault.

This conduct is now covered by the Sexual Offences Act 2003.


"False imprisonment" can depend upon D's beliefs.

If a constable, genuinely and reasonably believed that V was guilty of an offence, V will not have been falsely imprisoned whether he has actually committed an offence or not.


Whether imprisonment is false or not will turn, usually, not only on mere subjective belief in the legitimacy of the arrest, but also on the reasonableness of that belief.


This is certainly so with section 2 (2)-(7) Criminal Law Act 1967. But there still must be genuine suspicion. If a PC arrests someone without suspecting him to be guilty of an arrestable offence, he would be guilty of false imprisonment. Hence, the existence of the actus reus turns on the accused's mind.


Harnett v Bond [1925]

  • Harnett was classified as insane and kept in a mental institution managed by Dr Adam.

  • Dr Adam released Harnett on licence.

  • Harnett visited a Dr Bond, who decided that Harnett was insane, detained Harnett in his office and arranged for Harnett to return to Dr Adam's institution.

  • Harnett remained there for several years until he escaped and was judged by two psychiatrists to be sane.

  • It was clear that Dr Adam had believed Harnett to be mad throughout the time of Harnett's incarceration.

  • Harnett sued the doctors for false imprisonment.

Viscount Cave LC:

"The leave of absence order authorises the medical officer [Dr Adam] to retake the patient if the patient's mental condition requires it. If this power is exercised negligently, it may be that there is a remedy; but the negligence does not make the retaking unlawful, and the remedy (if any) is by action for negligence and not by action for false imprisonment." 

Hence, Dr Adamís attitude to Harnett meant there had been no actus reus of false imprisonment, either as a crime or as a tort.


The actus reus of theft includes appropriation.

Theft involves "appropriation" and this concept revolves around D's attitude to another's property that is, an assumption of the rights of the owner.


Professor Smith in The Law of Theft:

"It is impossible to determine whether there has been an appropriation without having regard to the intention with which an act was done." 

Ignorance as to the lack of insurance is no bar to conviction for permitting the use of an uninsured vehicle

There must be a conscious decision to allow another to use the vehicle. So, if E believes that when D nods he is agreeing to E driving D's car when, in fact, D was nodding in reply to another question, D has not permitted E to drive his car.

In all cases involving "to permit," in the actus reus the mind of the accused is involved.

In a certain type of manslaughter the actus reus is not merely that V dies as a result of D's neglect, but that V was D's had assumed responsibility for V. This only arises where D voluntarily assumes the care of V.

In R v Stone [1977] the court inferred that the accused had assumed responsibility towards his sister, it is apparent that the basis of the court's decision was the existence of this voluntary assumption.

But the existence of this duty is a necessary part of the actus reus Without it the conduct is not prohibited, and yet its existence depends on the mind of the accused.


Two actus rea together with one mens rea

In Fagan v Metropolitan Police Commissioner [1968], the accused accidentally parked his car on a policeman's foot.

D realised what had occurred and decided to leave his car on PC Morris' foot. Eventually he moved it. He was convicted of assault. The activity of driving onto, and remaining on the foot was the actus reus. D became liable for that actus reus when he possessed mens rea.


The act of battery was the external basis of the charge and spanned driving onto the foot to removing the car but that liability proceeded from the joining of mens rea to this.


Fagan's crime was the single continuous assault. He could only be liable for that crime for those periods during which he had mens rea.


If Fagan had, after deciding to remain on the foot, wrongly thought his car had rolled off the foot but on discovering the truth, decided to stay put, this second occurrence of mens rea would not render him liable for a distinct assault.


There has been a break in mens rea, but the actus reus has continued uninterrupted. Hence, Fagan would have committed the one assault at these two separate times during which he had mens rea.


In Thabo Meli [1954] PC (South Africa) a break in mens rea is irrelevant to the termination of the crime 

Lord Reid's:

"[Their crime is not reduced] from murder to a lesser crime, merely because the accused were under some misapprehension for a time during the completion of their criminal plot." 

D's argument that there was no contemporaneity of actus reus and mens rea was rejected: the events were one transaction, during which malice aforethought had existed.


The actus reus stretched from the first blow to the eventual death. That was "the killing."


As mens rea existed at some time during that killing, they were liable for murder.


The emphasis is placed upon the identity of a crime with its actus reus and the requirement for liability that at some time during that actus reus there is mens rea.

If mens rea existed at two separate times during the one killing, D would only have committed one crime, although his liability for that single crime would exist at those two periods of time.


Fagan and Thabo Meli affirm the view that it is the actus reus that identifies the existence of and duration of a crime.


The removal of a mental element by voluntary consumption of alcohol (or drugs)

The criminal law sometimes holds that once the actus reus is established liability is complete. An example is the defence of voluntary intoxication.

If D is voluntary intoxication and so is incapable of forming the necessary mens rea, he will still be liable for that actus reus even though the crime usually requires proof of mens rea. (This is not the case if the crime charged is one of specific intent).


In R v Burns (1973) CA, D a homosexual, was charged with indecent assault. He claimed that he suffered a form of automatism resulting from the combination of psychiatric disturbance and alcohol and awoke to discover his penis in another man's mouth.


Held: Indecent assault is not a crime of specific intent.


If Burns had been unaware of his behaviour owing to intoxication, he would still be guilty of indecent assault.


If the assault was not deliberate and deliberately indecent, self-induced drunkenness is no defence to indecent assault because no specific intent is required.


Indecent assault is not a crime in which the accused must intentionally bring about the actus reus or in which some ulterior intent must be proved for liability. Hence, it is not a crime of specific intent. Whilst sexual purpose is a necessary ingredient of this crime, it relates to the existence of the actus reus, not the mens rea.


Burns was not relying on a defence of intoxication, rather, if his actions were unconscious or accidental, and thus not consciously sexual, there was no actus reus and so there was no indecent assault.


There can be no liability if there is no actus reus. Hence, a lack of sexual purpose for whatever reason negates liability.


The need for conscious sexuality means that the assault must be deliberate and there must be sexually purposeful.


Thus, the requirement of deliberateness as to the assault is not a requirement of mens rea but merely that the body contact be deliberate.


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