Truth of a statement may be relevant as to whether voluntary or not

DeClercq v. R., [1968] S.C.R. 902 holds:

I am in agreement with the conclusions stated in the Hammond case. While it is settled law that an inculpatory statement by an accused is not admissible against him unless it is voluntary, and while the inquiry on a voir dire is directed to that issue, and not to the truth of the statement, it does not follow that the truth or falsity of the statement must be irrelevant to such an inquiry. An accused person, who alleged that he had been forced to admit responsibility for a crime committed by another, could properly testify that the statement obtained from him was false. Similarly, where the judge conducting the voir dire was in some doubt on the evidence as to whether the accused had willingly made a statement, or whether, as he contended, he had done so because of pressure exerted by a person in authority, the admitted truth or the alleged falsity of the statement could be a relevant factor in deciding whether or not he would accept the evidence of the accused regarding such pressure.