A common law principle

12.1       There is a common law presumption that ‘mens rea, an evil intention, or a knowledge of the wrongfulness of the act, is an essential ingredient in every offence’.^[1] The general requirement of mens rea is said to be ‘one of the most fundamental protections in criminal law’,^[2] and it reflects the idea that

it is generally neither fair, nor useful, to subject people to criminal punishment for unintended actions or unforeseen consequences unless these resulted from an unjustified risk (ie recklessness).^[3]

12.2       Ashworth and Horder write:

The essence of the principle of mens rea is that criminal liability should be imposed only on persons who are sufficiently aware of what they are doing, and of the consequences it may have, that they can fairly be said to have chosen the behaviour and consequences.^[4]

12.3       Some criminal offences, however, do not require proof of fault—these are described as strict liability and absolute liability offences. The Terms of Reference for this Inquiry ask the ALRC to consider laws that apply strict or absolute liability to all physical elements of a criminal offence. However, at this stage of its inquiry, the ALRC is interested in submissions on offences with any strict or absolute liability element which people consider to be unjustified.

12.4       This chapter discusses the source and rationale of the mens rea principle; how the principle is protected from statutory encroachment; and when it may be justified to create a criminal offence that does not require proof of fault. The ALRC calls for submissions on two questions.

12.5       In Australia, criminal offences are generally characterised in one of three ways:

• mens rea offences—the prosecution must prove a physical element (actus reus) and a mental element (mens rea);

• strict liability offences—the prosecution is not required to prove fault, but there is a defence of reasonable mistake available;^[5] and

• absolute liability offences—proof of fault is not required and no defences are available.^[6]  

12.6       In He Kaw Teh v R (1985),Brennan J explained the operation of mens rea as an element in criminal offences:

It is implied as an element of the offence that, at the time when the person who commits the actus reus does the physical act involved, he either—

(a) knows the circumstances which make the doing of that act an offence; or

(b) does not believe honestly and on reasonable grounds that the circumstances which are attendant on the doing of that act are such as to make the doing of that act innocent.^[7]

12.7       Historically, criminal liability at common law necessarily involved proof of mens rea.^[8] In Williamson v Norris (1899), Lord Russell CJ said:

The general rule of the English law is that no crime can be committed unless there is mens rea.^[9]

12.8       In his Commentaries on the Laws of England (1765), William Blackstone wrote that, to ‘constitute a crime against human laws, there must be first a vicious will, and secondly, an unlawful act consequent upon such vicious will’.^[10]

12.9       However, as discussed further below, strict liability offences were increasingly developed in the mid to late 19th century, particularly so-called ‘regulatory offences’.^[11]

12.10   In Australia, the common law presumption of fault-based liability is also reflected in statute. Section 5.6 of the Criminal Code (Cth) creates a rebuttable presumption that, to establish guilt, fault must be proven for each physical element of a Commonwealth offence.