How to treat the testimony of an accomplice?

In applying that test to the circumstances of this case, I consider, first, that the principal witnesses against the person sought are accomplices, whose evidence must always be viewed carefully. In that regard, however, Vetrovec v. The Queen, (1982), 1982 CanLII 20 (SCC), 1 S.C.R. 811, Dickson J. wrote as follows in the context of considering the testimony of an accomplice and how to treat it: All that can be established is that the testimony of some accomplices may be untrustworthy, but this can be said of many categories of witness. There is nothing inherent in the evidence of an accomplice which automatically renders him untrustworthy. To construct a universal rule singling out accomplices, then, is to fasten upon this branch of the law of evidence a blind and empty formalism. Rather than attempting to pigeon hole a witness into a category and then recite a ritualistic incantation, the trial judge might better direct his mind to the facts of the case and thoroughly examine all the factors which might impair the worth of a particular witness. If, in his judgment, the credit of the witness is such that the jury should be cautioned, then he may instruct accordingly. If, on the other hand, he believes the witness to be trustworthy, then regardless of whether the witness is technically an accomplice, no warning need be given.