The terms Actus Reus and Mens Rea

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The terms Actus Reus and Mens Rea come from the Latin “actus non facit reum nisi mens sit rea”. The meaning of this Latin term translates as “an act  is not criminal in the absence of a guilty mind” This one sentence forms the basis for conviction under criminal law, the two key elements being the actus reus (criminal act) and the accompanying mens rea (guilty mind). Arising from this basis for criminal prosecution are the two legal principles of coincidence and causation. Coincidence refers to the temporal coincidence of both the actus reus and the mens rea. Causation goes beyond coincidence and establishes a chain of causation thus stretching out the actus reus and allowing the mens rea to overlap thus facilitating a conviction.

In order to show how the law has widened we must first establish and discuss the development of the basic law of coincidence. One of the first important cases on coincidence is Thabo Meli v R. . The case concerns a man being taken to a hut and intoxicated. He was hit over the head and the appellants believing him to be dead rolled his body over a cliff where he later died of exposure. The key issue raised here is that there are 2 acts; firstly the assault and secondly the act of rolling the victim over a cliff leading to his death from exposure. The first act was carried out with the requisite mens rea but the actus reus of murder/manslaughter was no present. The second act (the disposal of the supposed corpse) was carried out with no mens rea to cause harm as the defendants believed the victim to be dead however this second act did have the actus reus of murder/manslaughter. It can be seen that unless there is a point in time when both the actus reus and mens rea coincide, a conviction cannot be successfully made. This view is supported by Lord Reid’s dictum in the Thabo Meli v R. case:

“It is said that the mens rea necessary to establish murder is the intention to kill, and that there could be no intention to kill when the accused thought the man was already dead, so their original intention to kill had ceased before they did the act which caused the mans death.”

Following this case was that of R. v Church in which a man took a woman back to his vehicle for sexual purposes, after failing to satisfy her she rebuked him and he struck her over the head causing her to fall unconscious. Unable to wake the victim and believing her to be dead the accused threw the supposed corpse into the river. It was later revealed that her death was caused by drowning. The judge in this case makes an important direction to the jury. Edmund Davies J states:

“The unlawful act must be such as all sober and reasonable people would inevitably recognise must subject the other person to, at least the risk of some harm resulting there from, albeit not serious harm….”

This dictum in reference to Lord Atkins widens the rules slightly. Previous to this decision there was a prerequisite requirement of an intention to kill whereas now all that is required is that the defendant has the mens rea to cause some harm. A practical example of this is if A punches B intending to cause grievous bodily harm and B falls after the blow and cracks his head on the pavement and dies. A has the mens rea for harm and thus manslaughter can be considered.

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Another important case which shows the development of the law of coincidence is that of Fagan v Metropolitan Police Constabulary. This somewhat unusual case in which a man drove onto a police constables foot by accident and the refused to move off once he realised the accident illustrates the difficulties in establishing the temporal coincidence  of actus reus and mens rea. Fagan’s actus reus was driving onto the police constable’s foot which initially was accidental and without mens rea thus there is no crime. However, at the point which Fagan realised the situation and that the actus reus had ...

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