The terms actus reus and mens rea derived from Edward Coke’s statement that ‘actus non facit reum nisi mens sit rea’. Simply put, that an act does not make a person guilty unless their mind also makes them guilty. Hence, the general test at British law is one that requires proof of fault, culpability or blameworthiness in both behaviour and mind.
Unlawful Conduct
In reality, actus reus consists of more than just an act. It also consists of whatever circumstances and consequences are required for the offence in question – in other words, all the elements of the offence except those relating to the mental state of the defendant.
Crimes can be divided into two categories:
- First, there are conduct crimes, where the actus reus is the prohibited conduct itself. For example, the actus reus of the offence of dangerous driving is simply ‘driving a mechanically propelled vehicle on a road or other public place’ (s2 Road Traffic Act 1988). No harm or consequence of the dangerous driving needs to be established in order for the defendant to be guilty.
- Secondly, there are result crimes, where the actus reus of the offence requires proof that the conduct caused a prohibited consequence or result. For example, the actus reus of criminal damage is that property belonging to another must have been damaged or destroyed ( s1(1) Criminal Damage Act 1971).
Voluntary Conduct
It is further required that actus reus must be voluntary, although ‘involuntary’ is defined narrowly and would normally only apply to situations where the defendant is not in control of their own body.
One example where a defendant’s conduct is not voluntary is in instances of automatism. Automatism is where the defendant performs a physical act but is unaware of what he is doing, or is not in control of his actions, due to some external factor.
Also, a defendant may have responded to something with a spontaneous reflex over which they had no control, as was the case in Hill v Baxter [1958] where the defendant was stung by a swarm of bees while driving and lost control of the car.
State of Affairs Crimes
State of affairs crimes cannot be discussed in terms of voluntary acts. Such crimes are defined not in the sense of the defendant doing a positive act but consist instead, for example, of the defendant ‘being found’, ‘being in possession’ or ‘being in charge’. In cases involving this kind of crime, all that needs to be proved is the existence of the factual circumstances that constitute the crime.
Omissions
The general rule of British law is that there can be no liability for failure to act so a defendant cannot be punished for not doing something. However, the exception to this is if the defendant had a duty to act and broke that duty. There are only limited circumstances in which the defendant has a duty to act, for example the Children and Young Persons Act 1933 creates an offence of wilfully neglecting a child.
Sources:
Herring, J. (2008) Criminal Law: Text, Cases and Materials (Oxford: OUP)
Elliott, K. & Quinn, F. (2008) Criminal Law (Longman)
Allen, M. (2007) Textbook on Criminal Law (Oxford: OUP)
