A common law privilege

10.1       The privilege against self-incrimination is ‘a basic and substantive common law right, and not just a rule of evidence’.^[1] It reflects ‘the long-standing antipathy of the common law to compulsory interrogations about criminal conduct’.^[2]

10.2       This chapter discusses the source and rationale of the privilege; how this privilege is protected from statutory encroachment; and when laws that encroach on this privilege may be justified.

10.3       The ALRC calls for submissions on two questions about this privilege.

10.4       The right to claim the privilege against self-incrimination in criminal law and against self-exposure to penalties in civil and administrative law entitles a natural person^[3] to refuse to answer any question or produce any document if it would tend to incriminate them.^[4]

10.5       In its 2005 report on uniform evidence law, the ALRC explained the three categories of the privilege:

Although broadly referred to as the privilege against self-incrimination, the concept encompasses three distinct privileges: a privilege against self-incrimination in criminal matters; a privilege against self-exposure to a civil or administrative penalty (including any monetary penalty which might be imposed by a court or an administrative authority, but excluding private civil proceedings for damages); and a privilege against self-exposure to the forfeiture of an existing right (which is less commonly invoked).^[5]

10.6       The privilege arose from the common law maxim nemo tenetur prodere seipsum, meaning that people should not be compelled to betray themselves.^[6] The ius commune or common law of the 12th and 13th centuries, a combination of the Roman and canon laws, included an early privilege against self-incrimination that influenced the modern iteration of the privilege at common law.^[7]

10.7       In his Commentaries on the Laws of England (1765-1769), William Blackstone explained that the maxim was enlivened where a defendant’s ‘fault was not to be wrung out of himself, but rather to be discovered by other means and other men’.^[8]

10.8       Jeremy Bentham was a fierce critic of the privilege, arguing in 1827 that the privilege had the inevitable effect of excluding the most reliable evidence of the truth—that which is available only from the person accused.^[9]

10.9       There is some debate among legal historians about the origins of the privilege.^[10]  Professor John Langbein points to the development of the privilege as part of the rise of the adversarial criminal justice system where the prosecution is charged with proving the guilt of a defendant beyond a reasonable doubt and subject to protections surrounding the manner of criminal discovery.^[11]

10.10   Others point to the development of the privilege in the 17th century as a response to the unpopularity of the Star Chamber in England whose practices included requiring suspects on trial for treason to answer questions without protection from self-incrimination.^[12]

10.11   The protection afforded by the privilege may encourage people to cooperate with investigators and prosecutors, where otherwise they may fear the risk of self-incrimination:

it is thought that without such protections witnesses might be loath to come forward to give evidence.^[13]

10.12   In criminal law, the privilege offers some protection against any perceived power imbalance between the prosecution and a defendant.^[14]

10.13   It has also been suggested that the right to claim the privilege against self-incrimination may protect individuals from unlawful coercive methods used to obtain confessions.^[15]

10.14   A corollary of this rationale is that the stressful environment of police interviews may be ‘conducive to false confessions on account of the authority of police, the isolation, uncertainty and anxiety of the suspect and the expectations of the interrogation officer’.^[16] These factors may place pressure on defendants to provide information which may incriminate them, is prejudicial to their case, or even information which is false. The right to claim the privilege against self-incrimination can act as one safeguard against the false confession of nervous, yet innocent, defendants.^[17]

10.15   The privilege has been described by the High Court as a ‘fundamental bulwark of liberty’.^[18] The privilege has also been said to protect human dignity by providing a ‘shield against conviction by testimony wrung out of the mouth of the offender’.^[19] In Pyneboard Pty Ltd v Trade Practices Commission, Murphy J stated that

The privilege against compulsory self-incrimination is part of the common law of human rights. It is based on the desire to protect personal freedom and human dignity. These social values justify the impediment the privilege presents to judicial or other investigation. It protects the innocent as well as the guilty from the indignity and invasion of privacy which occurs in compulsory self-incrimination; it is society’s acceptance of the inviolability of the human personality.^[20]

Statutory protection

10.16   Some legislative provisions codify the principle against self-incrimination. For example, s 128(1) of the uniform Evidence Acts provides that where a witness objects to giving particular evidence that ‘may tend to prove’ that the witness has committed an offence under Australian or foreign law, or is liable to a civil penalty, a court may determine whether there are ‘reasonable grounds’ for an objection to providing that evidence.