What is the three-part test for getting an interlocutory injunction in Ontario?

Ontario courts generally assess a request for an interlocutory (temporary, pre-trial) injunction using a three-part framework developed through the common law. First, is there a serious issue to be tried - a genuine question worth the court's attention, not a frivolous or hopeless claim, which is usually a fairly low threshold to meet. Second, would the applicant suffer irreparable harm if the injunction isn't granted - harm that can't be adequately compensated later with money damages, such as loss of a unique property interest, permanent reputational damage, or a business that would be destroyed before trial could even happen.

Third, does the balance of convenience favour granting the injunction - weighing the harm to the applicant if it's refused against the harm to the other side if it's granted, along with the broader public interest where relevant. All three factors are considered together rather than treated as strict independent hurdles, and courts have some flexibility in how they weigh them against each other depending on the strength of the case and the seriousness of the harm involved. Because irreparable harm and balance of convenience are often the real battlegrounds, detailed evidence on both - not just an assertion the case is strong - matters enormously to the outcome.