Authors Sinclair Prowse and E. Bennett wrote:
"As with all defenses, (a proposed defense) cannot be left to the jury unless there is an air of reality to it. That is, the trial judge must determine if there is an evidentiary foundation to the defense..... Specifically, the trial judge must determine if the evidence put forward its sets that if believed, a reasonable jury properly charged could have acquitted."
The Supreme Court of Canada considered the issue in R v Cinous and attempted a codification of the law as follows at ¶51, ¶53 and ¶81:
"The basic requirement of an evidential foundation for defences gives rise to two well-established principles.
"First, a trial judge must put to the jury all defences that arise on the facts, whether or not they have been specifically raised by an accused. Where there is an air of reality to a defence, it should go to the jury.
"Second, a trial judge has a positive duty to keep from the jury defences lacking an evidential foundation. A defence that lacks an air of reality should be kept from the jury.
" In applying the air of reality test, a trial judge considers the totality of the evidence, and assumes the evidence relied upon by the accused to be true. See Osolin, supra; Park, supra. The evidential foundation can be indicated by evidence emanating from the examination in chief or cross-examination of the accused, of defence witnesses, or of Crown witnesses. It can also rest upon the factual circumstances of the case or from any other evidential source on the record. There is no requirement that the evidence be adduced by the accused.
"The question to be asked by the trial judge in applying the air of reality test is whether there is evidence upon which a properly instructed jury acting reasonably could acquit if it accepted the evidence as true."
REFERENCES:
- R v Cinous (2002) 2 SCR 3
- R v SRB 2009 ABCA 45
- Sinclair Prowse, J. and Bennett, E., Working Manual of Criminal Law, "Defences" (Toronto: Thomson-Carswell, 2009), pages 2-3 and 66.17.