Public policy and private illegality in the pursuit of evidence

Abstract

The public policy discretion at common law in Australia was established in the High Court case of Bunning v Cross. The discretion has subsequently been interpreted and applied to permit courts to exclude evidence obtained by improper, unlawful or illegal conduct on the part of ‘the authorities’. The discretion has not been held to be enlivened for exercise in circumstances where the impugned conduct is on the part of private persons unconnected with law enforcement. This article argues that this fetter on the availability of the public policy discretion has been wrongly interpreted from the decision in Bunning and that, to the extent that the fetter now forms part of the common law discretion, it should be abandoned. The argument is made on the basis of the language, context, development and rationale of the public policy discretion as conceived in Bunning. The statutory Uniform Evidence Law, which applies in certain Australian jurisdictions, enacts a public policy discretion in s. 138 drawn from the common law public policy discretion. The Uniform Evidence Law is examined to indicate the absence of any fetter to the s. 138 discretion applying only to conduct by authorities as a basis for revising the understanding of the common law discretion. The comparable powers to exclude unlawfully obtained evidence in the United States and United Kingdom are examined to distinguish the rationale of the Australian discretion as requiring a broader scope of application. The internet is considered as a modern advent permitting previously unknown capacity for private persons to unlawfully police each other. Private criminal investigation through the internet is argued to be a further basis to mark the need for the extension of the Australian public policy discretion to all persons not only the authorities. The overarching thesis of this article is to demonstrate why the Australian common law public policy discretion should be enlivened by improper, unlawful or illegal conduct, regardless of the source of that conduct.