Warnings about unreliable evidence

18.18 Historically, certain categories of witnesses were regarded as unreliable, and the common law required the trial judge to warn the jury about the dangers of relying on such evidence where it was uncorroborated. These categories included: complainants in sexual assault cases,[54] accomplices,[55] and child witnesses.[56] The rationale for corroboration warning requirements was explained by Brennan J in Bromley v The Queen as follows:

The courts have had experience of the reasons why witnesses in the three accepted categories [accomplices, children, sexual assault complainants] may give untruthful evidence wider than the experience of the general public, and the courts have a sharpened awareness of the danger of acting on the uncorroborated evidence of such witnesses. The experience of the courts has shown also that the reasons which may lead one suspect witness to give untruthful evidence are not necessarily the same as the reasons why another suspect witness may do so.[57]

18.19 Corroboration warnings generally require the trial judge to do the following: identify the risks of unreliability of the particular type of evidence; direct the jury that it is dangerous to act upon such evidence where it is uncorroborated; define corroboration and draw the jury’s attention to any other evidence adduced at trial which may be capable of corroborating the suspect evidence; and finally, instruct the jury that it may still act upon the suspect testimony alone if it is convinced of its accuracy beyond reasonable doubt.[58]

18.20 Warnings about the potential unreliability of categories of witnesses such as women and children are now recognised as discriminatory and based on prejudice rather than empirical evidence.

18.21 The common law corroboration warning requirements were criticised in ALRC 26 on the following basis:

The present law is too rigid and technical. There is a strong case for saying that it does not adequately serve the rationale of minimising the risk of wrongful convictions. Warnings can be required when not necessary and avoided when they should be given in the circumstances of the particular case. In addition, warnings in their present form distract attention from the issue of the reliability of the evidence in question. Finally, the directions to be given are so complex that they are likely to be ignored … What is required is a simpler regime, under which the trial judge must consider whether a direction appropriate to the circumstances should be given.[59]

18.22 Two options for reform were identified. The first was the abolition of the warning requirements and the introduction of an unguided discretion whereby trial judges could give warnings wherever it was considered appropriate to do so. The second was the introduction of a guided discretion, whereby categories of potentially unreliable evidence were retained, but the trial judge would only be required to give a warning if it were considered necessary in the circumstances of the case.[60] The ALRC preferred the latter for two reasons: first, accumulated judicial experience regarding certain types of evidence should be used; secondly, there was a risk that the introduction of an unguided discretion might simply lead to the redevelopment of the existing corroboration warnings regime.[61]

18.23 The ALRC recommendation included an exhaustive list of categories of evidence in respect of which a warning may be required. This list included categories corresponding to those which required corroboration warnings at common law[62] and new categories (such as hearsay evidence) in order to compensate for the more relaxed admissibility provisions. The ALRC recommended that the judge’s common law powers to give appropriate warnings and directions remain intact, suggesting that these general powers would be available to cover any new category of unreliable evidence that may emerge.[63]

18.24 In accordance with the recommendations in ALRC 26 and ALRC 38, s 164 of the uniform Evidence Acts abolishes the common law corroboration warning requirements,[64] and a more flexible warnings regime is introduced in s 165. However, s 165 differs from the provision proposed by the ALRC[65] in that it contains an inclusive list of categories of evidence in respect of which a warning may be given, and therefore applies generally to ‘evidence of a kind that may be unreliable’. Pursuant to s 165, the trial judge has the discretion to refuse to give a warning if there are ‘good reasons’ for doing so. In addition, the statutory warning does not require that any particular form of words be used. The provision therefore shifts the emphasis away from generalised warnings towards the particular risk in the circumstances of the case. However, the Acts do not prohibit the trial judge from giving a traditional corroboration warning,[66] and s 165(5) specifically retains the power of the trial judge to give common law warnings and directions (except where otherwise provided).

18.25 While traditional corroboration warnings can still be given, legislation has been passed in most Australian jurisdictions, including uniform Evidence Act jurisdictions, to prohibit or restrict the ability of trial judges to warn that a particular class of witness, notably sexual assault complainants and children, is inherently unreliable.[67] These reforms were implemented to reflect improved understanding of the reliability of the evidence given by children and sexual assault complainants. However, they have been significantly undermined by the development of a new class of common law warnings which bear many of the hallmarks of the traditional corroboration warning.

18.26 The expansion of the common law judicial warnings began with the decision of the High Court in Bromley v The Queen.[68] In this case, the court considered that a warning was required in respect of the unreliability of a particular witness who did not fall within one of the established categories requiring a corroboration warning. The court rejected the argument that the corroboration doctrine should be extended to cover witnesses of that category, but held that a judicial warning should be given wherever the unreliability of a particular witness has not been exposed adequately in cross-examination.[69]

18.27 The doctrine in Bromley was subsequently extended in Longman v The Queen, where it was held that a warning must be given to the jury ‘whenever … necessary to avoid a perceptible risk of miscarriage of justice arising from the circumstances of the case’.[70] The result has been to reinstate a near mandatory warning regime in relation to a number of categories of evidence, including: evidence of delayed complaint in sexual assault cases,[71] unrecorded admissions to investigators,[72] prosecution evidence given by prison informers,[73] and identification evidence.[74] These warning requirements have survived the statutory prohibitions on general warnings relating to particular classes of witnesses, as they purport to address the particular risk in the circumstances of the case in which they are given.[75]

18.28 The uniform Evidence Acts preserve the common law powers and obligations of the trial judge to give warnings, and there has been a steady expansion in the number of warnings that may be required in addition to those provided for by the uniform Evidence Acts.

[54]Kelleher v The Queen (1974) 131 CLR 534.

[55]Davies v Director of Public Prosecutions [1954] AC 378.

[56]Hargan v The King (1919) 27 CLR 13.

[57] Bromley v The Queen (1989) 168 CLR 79, 324.

[58] A Ligertwood, Australian Evidence (4th ed, 2004), [4.5].

[59] Australian Law Reform Commission, Evidence, ALRC 26 (Interim) Vol 1 (1985), [1015].

[60] Ibid, [1017].

[61] Ibid, [1009].

[62] Note that the ALRC draft provision retained the category of sexual assault complainants, however this category was omitted from s 165(1) of the uniform Evidence Acts: Australian Law Reform Commission, Evidence, ALRC 38 (1987), Appendix A (cl 140 of draft Evidence Bill 1987).

[63] Australian Law Reform Commission, Evidence, ALRC 26 (Interim) Vol 1 (1985), [1017].

[64] Except in relation to perjury and similar offences: s 164(2).

[65] Australian Law Reform Commission, Evidence, ALRC 38 (1987), Appendix A (cl 140 of draft Evidence Bill 1987).

[66]Conway v The Queen (2002) 209 CLR 203, [53].

[67] See discussion below.

[68] Bromley v The Queen (1989) 168 CLR 79.

[69] Ibid.

[70]Longman v The Queen (1989) 168 CLR 79, 87.

[71] Ibid.

[72] McKinney v The Queen (1991) 171 CLR 468.

[73]Pollitt v The Queen (1992) 174 CLR 558.

[74] Domican v The Queen (1992) 173 CLR 555.

[75] Robinson v The Queen (1999) 197 CLR 162.