When will a court strike a third party claim?

Rosenberg J.A., speaking for the court, upheld the decision of the motions judge to strike the third party claim and in the course of giving reasons discussed the various approaches to assessing damages in multi accident cases. The court assumed that the defendant was correct in asserting that there was a single indivisible injury and that Athey v. Leonati would apply (at para. 17). Justice Rosenberg went on to state that although as a result both tortfeasors would be fully liable for the injury, the court would still have to apportion responsibility between them, even though the first tortfeasor was not a party to the action. He went on to find that at the trial the court would determine both the amount of damages suffered by the plaintiff and the degree of responsibility attributable to the second accident.