A common law principle

11.1       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] The High Court of Australia observed in 2014 that

[o]ur system of criminal justice reflects a balance struck between the power of the State to prosecute and the position of an individual who stands accused. The principle of the common law is that the prosecution is to prove the guilt of an accused person.^[3]

11.2       This principle and the related principle that guilt must be proved beyond reasonable doubt are fundamental to the presumption of innocence.^[4]

11.3       This chapter discusses the source and rationale for the principle that the burden of proof is borne by the prosecution; how this principle is protected from statutory encroachment; and when laws that reverse the onus of proof in criminal trials may be justified.

11.4       This chapter is about the burden of proof in criminal, rather than civil, law. It considers examples of criminal laws that reverse the legal burden of proof. However, it also briefly discusses some laws that reverse the onus of proof in civil matters that were raised by submissions to this Inquiry.

11.5       The presumption of innocence has been recognised since ‘at latest, the early 19th Century’.^[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’.^[6] In 2005, the House of Lords said that the underlying rationale for the presumption of innocence was that to place the burden of proof on a defendant was ‘repugnant to ordinary notions of fairness’.^[7]

11.6       Professor Andrew Ashworth has expanded on the rationale 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.^[8]

11.7       In the High Court of Australia, French CJ called the presumption of innocence ‘an important incident of the liberty of the subject’.^[9]

11.8       However, the principle that the accused does not bear a legal burden of proof has not been treated as unqualified. The legal burden of proving the defence of insanity rests on the party that raises it. Additionally, Parliament may reverse the onus of proof.^[10] In 2014, the High Court noted that

[i]t has long been established that it is within the competence of the legislature to regulate the incidence of the burden of proof.^[11]

11.9       In Williamson v Ah On, Isaacs J suggested that it may be justified in some circumstances to reverse the burden of proof:

The broad primary principle guiding a Court in the administration of justice is that he who substantially affirms an issue must prove it. But, unless exceptional cases were recognized, justice would be sometimes frustrated and the very rules intended for the maintenance of the law of the community would defeat their own object. The usual path leading to justice, if rigidly adhered to in all cases, would sometimes prove but the primrose path for wrongdoers and obstruct the vindication of the law.^[12]

Legal and evidential burdens

11.10   There is a distinction between a legal and an evidential burden of proof. These terms are defined in the Criminal Code (Cth):

legal burden, in relation to a matter, means the burden of proving the existence of the matter.^[13]

evidential burden, in relation to a matter, means the burden of adducing or pointing to evidence that suggests a reasonable possibility that the matter exists or does not exist.^[14]

11.11   Generally, the prosecution will bear both the legal and evidential burden of proof.^[15] However, an offence may be drafted so that the accused bears either the evidential or legal burden, or both, on some issues.^[16] Lord Hope in the House of Lords described what it means for the accused to bear either the legal or evidential burden of proof on an issue:

A ‘persuasive’ [legal] burden of proof requires the accused to prove, on a balance of probabilities, a fact which is essential to the determination of his guilt or innocence. It reverses the burden of proof by removing it from the prosecution and transferring it to the accused. An ‘evidential’ burden requires only that the accused must adduce sufficient evidence to raise an issue before it has to be determined as one of the facts in the case. The prosecution does not need to lead any evidence about it, so the accused needs to do this if he wishes to put the point in issue. But if it is put in issue, the burden of proof remains with the prosecution. The accused need only raise a reasonable doubt about his guilt.^[17]

11.12   The Guide to Framing Commonwealth Offences states that ‘placing a legal burden of proof on a defendant should be kept to a minimum’.^[18] This principle is also reflected in the Criminal Code,which provides that where the law imposes a burden of proof on the defendant, it is an evidential burden, unless the law expresses otherwise.^[19]

11.13   This chapter is largely concerned with laws that reverse the legal burden of proof, rather than the evidential burden of proof. In other jurisdictions, an evidential burden of proof is not generally considered to offend the presumption of innocence.^[20] For example, in R v DPP; Ex parte Kebilene, Lord Hope said:

Statutory presumptions which place an ‘evidential’ burden on the accused, requiring the accused to do no more than raise a reasonable doubt on the matter with which they deal, do not breach the presumption of innocence.^[21]

11.14   It is beyond the practical scope of this Inquiry to consider whether particular reversals of the evidential burden of proof are justified.^[22] However, Professor Jeremy Gans submitted that placing an evidential burden on an accused can be problematic, ‘especially where the reversal applies to a key culpability element of a serious criminal offence’.^[23]

11.15   The Parliamentary Joint Committee on Human Rights (Human Rights Committee) has stated that

an offence provision which requires the defendant to carry an evidential or legal burden of proof will engage the right to be presumed innocent because a defendant’s failure to discharge the burden of proof may permit their conviction despite reasonable doubt as to their guilt.^[24]

Essential elements of offence

11.16   It is possible to distinguish between the defining elements of an offence (its physical and mental—or ‘fault’^[25]—elements) and an exception, exemption, excuse, qualification or justification to it (often referred to as defences).^[26] Such defences include, for example, self-defence or duress.

11.17   Generally, the prosecution bears the legal burden of proving the defining elements of an offence, as well as the absence of any defence. However, the accused will generally bear an evidential burden of proof in relation to defences. This is reflected in s 13.3(3) of the Criminal Code, which provides:

A defendant who wishes to rely on any exception, exemption, excuse, qualification or justification provided by the law creating an offence bears an evidential burden in relation to that matter. The exception, exemption, excuse, qualification or justification need not accompany the description of the offence.

11.18    Part 2.3 of the Criminal Code contains the generally available defences, and s 13.3(2) of the Criminal Code provides that the defendant bears the evidential burden of those defences.