In Simmons v. Yeager Properties Inc., 2014 BCCA 201 (released on May 20, 2014 so on the BCCA website soon after that) Lowry JA ( A. MacKenzie JA and Goepel JA concurring) wrote:

[8] … The default framework for causation was described in Clements v. Clements, 2012 SCC 32, as follows:

[8] The test for showing causation is the “but for” test. The plaintiff must show on a balance of probabilities that “but for” the defendant’s negligent act, the injury would not have occurred. Inherent in the phrase “but for” is the requirement that the defendant’s negligence was necessary to bring about the injury ― in other words that the injury would not have occurred without the defendant’s negligence. This is a factual inquiry. If the plaintiff does not establish this on a balance of probabilities, having regard to all the evidence, her action against the defendant fails.

In Ediger v Johnston, 2013 SCC 18,  [2013] 2 SCR 98, the unanimous (albeit “only” 7 member panel) agreed, in reasons  written jointly by Rothstein and Moldaver JJ:

[28]   This Court recently summarized the legal test for causation in Clements v. Clements, 2012 SCC 32,  [2012] 2 S.C.R. 181.  Causation is assessed using the “but for” test (Clements, at paras. 8 and 13; Resurfice Corp. v. Hanke, 2007 SCC 7,  [2007] 1 S.C.R. 333, at paras. 21-22). That is, the plaintiff must show on a balance of probabilities that “but for” the defendant’s negligent act, the injury would not have occurred (Clements, at para. 8).  “Inherent in the phrase ‘but for’ is the requirement that the defendant’s negligence was necessary to bring about the injury — in other words that the injury would not have occurred without the defendant’s negligence”  (para. 8 (emphasis deleted)).

Even if the point in Ediger has been slow to make it this far west, for whatever reason,  there’s now Simmons v. Yeager.

[Link updated to CanLII link – 15 Dec 2014]