Parliament, not the judiciary, may expand the scope of criminal liability.

Criminal offences in Canada since 1955 have been entirely statutory (with the exception of criminal contempt). However, the common law continues to play an important role in defining criminal conduct. 

However, where a court is asked to expand criminal liability by departing from the well-understood common law meaning of a term, three principles of statutory interpretation are particularly salient:

1.       When Parliament uses a legal term with a well-understood legal meaning, it is presumed that Parliament intended to incorporate that legal meaning into the statute.

2.       Any departure from that legal meaning must be clear, either by express language or necessary implication from the statute.

3.       Apart from criminal contempt, there can be no liability for common law crimes. Creating and defining crimes is for Parliament; the courts must not expand the scope of criminal liability beyond that established by Parliament.

R. v. D.L.W., 2016 SCC 22 (CanLII)

Applying these principles of statutory interpretation in R. v. D.L.W., the Supreme Court of Canada held that penetration was an essential element of the offence of bestiality.

Additional Notes

Parliament intends the legal meaning of legal terms–When Parliament uses a term with a legal meaning, it intends the term to be given that meaning.  Words that have a well-understood legal meaning when used in a statute should be given that meaning unless Parliament clearly indicates otherwise. Parliament is presumed to know the legal context in which it legislates and does not intend to disturb well-settled law without explicit language  or by “relying on inferences that could possibly be drawn from the order of certain provisions in the Criminal Code.

 Principle of stability in the law–Absent clear legislative intention to the contrary, a statute should not be interpreted as substantially changing the law, including the common law.