Seven years ago, a majority of the High Court in Tofilau v R  HCA 39 upheld four Victorian convictions founded on an unusual criminal investigative method. The method (known in Australia as ‘scenario’ evidence) is for undercover police officers to recruit suspected criminals into fake criminal gangs and then trick them into confessing real crimes by telling them that such confessions are a requirement for membership. After further prompts (such as staged inquiries from real police and promised aid from ‘corrupt’ police), the scenario culminates in a detailed, videotaped interview with the gang’s ‘boss’, after which the sting is revealed to the stunned suspect. This astonishing method (whose details can only be published thanks to a 2005 High Court ruling rejecting a publication ban) was developed in Canada, and the High Court in 2007 relied heavily on its repeated endorsement by the Canadian Supreme Court in upholding its use here.
However, last week, Canada’s top court unanimously changed its mind on the scenario (known there as ‘Mr Big’ Evidence), stepping back from its previous description of it as ‘skillful police work’ and instead developing a new rule that confessions produced are presumptively inadmissible, unless the prosecution can prove that the confession was reliable and that the police’s methods did not entrap the suspect into behaviour that would inevitably prejudice his or her trial. In the case before it, the Court unanimously held that a man’s detailed confession to drowning his two children was inadmissible, because of the lack of corroboration of his confession and the destitute and lonely man’s vulnerability to a police sting that briefly let him live a criminal’s high life.
The Canadian court’s volte-face has no immediate implications for the admissibility of such schemes in Australia. The common law the High Court applied in Tofilau has been replaced in most of Australia by a uniform evidence statute that exempts undercover schemes from its test for the reliability of confessions. In testing the admissibility of such evidence, Australian courts are likely to be influenced by another High Court judgment from 2007, where Gleeson CJ and Heydon J casually observed that, in Australia, ‘every day police officers take advantage of the ignorance or stupidity of persons whom they eventually prosecute’. Rather, the lesson for Australian police officers planning such schemes is that they cannot assume that a national court will maintain its support for such methods forever.