The Court must be very careful to ensure only admitted evidence is considered at trial

R.v. Smith deals with the unfortunate situation where materials not admitted into evidence were considered at trial. Specifically, a transcript of an interview found its way to the judge who relied on it. The transcript was never proven; it is unclear how the judge got it. The Court of Appeal is very clear such a problem can lead to a new trial:

These observations bring into focus problems that arise when proper attention is not paid to the boundaries of the trial evidence. Both counsel and the trial judge are responsible for ensuring that there is no confusion about what is and what is not available to the trier of fact for the purposes of deciding the case. Here, where Crown counsel wished to make use of the prior statements for the permissible purpose of rebutting the defence of fabrication, the Crown was obliged to decide first whether the entire statement or statements or just a portion were required, then to seek a ruling on the admission of what the Crown determined was necessary and finally, to ensure that what was admitted into evidence was limited to the information tendered and ruled admissible and nothing more. In some instances, for example, this may require redacting a portion of the page of a document to ensure that information not in evidence does not inadvertently become part of the record. Similarly, the trial judge has an obligation to monitor the admission of evidence carefully in order to ensure not only that the record is restricted to the material ruled admissible, but also that the evidence is used only for the purpose for which it was admitted (see: R. v. Morrisey (1995), 22 O.R. (3d) 514.)

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In my view, the appellant has demonstrated that the convictions in relation to counts one, two, four, five, six, seven and eight depended on material not in evidence and this material played an essential part in his conviction of the appellant. While the trial judge did not mention B.L’s previous consistent statements in his analysis of count four and the Crown’s case was supported by the testimony of other witnesses, reasons are to be read as a whole and I am not satisfied the trial judge’s conviction on count four was not tainted by the material not in evidence. Where a miscarriage of justice within the meaning of s. 686(1)(a)(iii) of the Criminal Code has been demonstrated, the appellant does not need to show that the verdict cannot be supported by the evidence within the meaning of s. 686(1)(a)(i). It follows that, in relation to these counts, the convictions must be quashed.