In R v McNeil  SCC 3 (16 January 2009) the Supreme Court of Canada, in a unanimous judgment delivered by Charron J, addressed the disclosure obligations which apply at common law to the Crown and to the police. Of particular interest is the potentially difficult bridging of the information gap that may exist between the Crown and the police. Is the prosecutor obliged to make inquiries of the police for all information that could be relevant to the defence? Are the police obliged to volunteer such information to the prosecutor?
The Court refrained from laying down specific rules, but stated principles.
In this case (where the point was moot as the Court of Appeal had set aside the convictions and the Crown undertook not to re-prosecute Mr McNeil, but the Supreme Court appointed an amicus curiae to argue the issue) the arresting police officer – the Crown's main witness - had been subject to a police investigation concerning drug-related misconduct which had culminated in disciplinary proceedings and a plea of guilty to a criminal charge. At the time of Mr McNeil's trial the police had a file concerning the disciplinary proceedings against, and criminal investigation of, the arresting officer.
The Supreme Court held (53) that the police have a duty to disclose to the Crown prosecutor disciplinary procedure information where it is relevant and its discovery should not be left to happenstance. In deciding relevance the police may well be advised to seek the assistance of Crown counsel (59). The issue was not to be decided by reference to whether there was any reasonable expectation of privacy (11) [in this regard, contrast s 29(3)(c) Criminal Disclosure Act 2008[NZ] – not yet in force].
The police and Crown's duty of disclosure to the defence of fruits of the investigation was established in R v Stinchcombe  3 SCR 326.
There are some shortcomings in the above New Zealand legislation which become apparent when McNeil is considered. The Criminal Disclosure Act 2008 does not put an obligation on the Crown to seek information from the police (s 15), and it only requires relevant convictions known to the prosecutor to be disclosed (s 13(3)(d)). I have previously commented on the "wide rule/wide request/fairly wide enforceability" structure of this legislation: see blog on McDonald v HM Advocate  UKPC 46, 21 October 2008.
The guidance set out in McNeil can be compared with the approach to claims of public interest immunity laid down in R v H  UKHL 3, where the primary and essential requirement is trial fairness to the accused.