Presumption Against the Retroactive Operation of a Statute

There is a difference between the two terms  A statute operates retroactively where it changes the past legal consequences of completed transactions: [R. Sullivan, Driedger on the Construction ofStatutes, 3rd ed.] (Toronto: Butterworths, 1994) at 511; Hornby Island Trust, 1988 CanLII 3143 (BC C.A.), (1988), 53 D.L.R. (4th) 435 at 441 (B.C. C.A.)supra at 441.

 In the leading case on the retroactive operation of statutes, Gustavson Drilling (1964) Ltd. v. M.N.R., [1977] S.C.R. 271, the Supreme Court of Canada outlined the general rule regarding retroactive statutes. Dickson J. (as he then was), for the majority, stated at 279 that:

The general rule is that statutes are not to be construed as having retrospective [retroactive] operation unless such a construction is expressly or by necessary implication required by the language of the Act. An amending enactment may provide that it shall be deemedto have come into force on a date prior to its enactment or it may provide that it is to be operative with respect to transactions occurring prior to its enactment. In those instances the statute operates retrospectively [retroactively].

As retroactive legislation frequently interferes with vested rights, the court presumes that, if the Legislature intended to interfere, it would have said so clearly. A statute will not be given retroactive construction unless it is clear that the Legislature intended such a construction: Hornby Island Trust, 1988 CanLII 3143 (BC C.A.), (1988), 53 D.L.R. (4th) 435 at 441 (B.C. C.A.)supra.

 The presumption against the retroactive operation of statutes, therefore, may only be rebutted by clear language in the statute. If the wording of an enactment is such that the Legislature must have intended to prescribe a new legal regime to a set of facts entirely concluded prior to the coming into force of the enactment, the enactment is retroactive and the presumption against retroactive operation is rebutted.CNG Producing Co. v. Alberta (Provincial Treasurer), 2002 ABCA 207 (CanLII)