A common law principle

9.1          In criminal trials, the prosecution bears the burden of proof. This has been called ‘the golden thread of English criminal law’[1] and, in Australia, ‘a cardinal principle of our system of justice’.[2] This principle and the related principle that guilt must be proved beyond reasonable doubt are fundamental to the presumption of innocence.[3]

9.2          However, Parliament can reverse the onus of proof:

It has long been established that it is within the competence of the legislature to regulate the incidence of the burden of proof.[4]

9.3          This chapter discusses the source and rationale for this principle; how this principle is protected from statutory encroachment; and when laws that reverse the onus of proof in criminal trials may be justified.[5] The ALRC calls for submissions on two questions about this presumption.

Question 9–1              What general principles or criteria should be applied to help determine whether a law that reverses or shifts the burden of proof is justified?

Question 9–2              Which Commonwealth laws unjustifiably reverse or shift the burden of proof, and why are these laws unjustified?

9.4          The presumption of innocence developed at common law towards the end of the 18th century.[6] In his Commentaries on the Laws of England (1765), William Blackstone said that ‘it is a maxim of English law that it is better that ten guilty men should escape than that one innocent man should suffer’.[7]

9.5          In 1935 the UK House of Lords said the presumption of innocence principle was so ironclad that ‘no attempt to whittle it down can be entertained’.[8] More recently, the House of Lords has said that shifting the burden of proof onto a defendant was ‘repugnant to ordinary notions of fairness’.[9]

9.6          In the High Court of Australia, French CJ called the presumption of innocence ‘an important incident of the liberty of the subject’.[10]

9.7          Andrew Ashworth has summarised some of the rationales for the presumption of innocence.

[T]he presumption is inherent in a proper relationship between State and citizen, because there is a considerable imbalance of resources between the State and the defendant, because the trial system is known to be fallible, and, above all, because conviction and punishment constitute official censure of a citizen for certain conduct and respect for individual dignity and autonomy requires that proper measures are taken to ensure that such censure does not fall on the innocent.[11]

9.8          The Guide to Framing Commonwealth Offences provides that ‘placing a legal burden of proof on a defendant should be kept to a minimum’.[12] This rule is also reflected in the Criminal Code Act 1995 (Cth) which provides that where the law imposes a burden of proof on the defendant, it should be an evidential burden,[13] unless the law expresses otherwise.[14]