What is the test for injunctive relief in a trade dispute?

With that, I turn to the foundation of principle upon which the companies’ case rested. I begin with the same general observations I made in Potash Corporation v. Todd (at p. 491): “These actions are, of course, rooted in the law of tort. And picketing per se is not actionable when carried on during lawful strikes; it is not subject to restraint in civil actions unless it involves the commission of a tort of concern to the plaintiff, one that interferes, for example, with the ownership or enjoyment of his land (as in trespass or nuisance), or with his person or reputation (defamation), or with his economic relations (as in procuring or inducing breach of contract or intimidation). So to the extent picketing may be accompanied by an independent tort, such as trespass, intimidation, defamation and so on; or may form an essential ingredient of another, such as inducing breach of contract; or may itself constitute a tort such as that of nuisance, then that picketing may -- so far as the plaintiff’s legal rights are being interfered with -- be restrained. Otherwise it may not. And such restraint as may be put upon the defendant should not in general extend beyond the tortious conduct complained of and established by the plaintiff. “So the determination of an application for injunctive relief in a civil action arising out of a trade dispute begins, just as it does in any other action, with the pleadings. The statement of claim constitutes the foundation upon which the plaintiff will have built his case for the interlocutory relief he seeks. It is necessary, therefore, to go first to the statement of claim and to identify which of the potentially applicable torts the plaintiff is relying upon. Having done that, it is then necessary to recall in detail the nature of the tort or torts in issue so as to be able to construct the framework of principle by which the lawfulness of the picketing falls to be determined.”