What is an Anton Piller order and how does it differ from a Mareva injunction in Ontario?

An Anton Piller order is an extraordinary, common law-based court order allowing a plaintiff, accompanied by an independent supervising lawyer, to enter a defendant's premises without advance warning to search for and preserve evidence - typically documents, electronic records, or counterfeit goods - that the plaintiff has real grounds to fear the defendant would otherwise destroy or hide once they knew a lawsuit was coming. It exists to protect evidence for the case, which is a fundamentally different purpose from a Mareva injunction, which freezes assets to make sure a future judgment can actually be collected.

Because an Anton Piller order authorizes what would otherwise be an unlawful search of someone's property, courts apply an even more demanding test than for a Mareva injunction, generally requiring an extremely strong prima facie case, clear evidence the defendant possesses specific, identifiable material that's genuinely at risk of being destroyed, and that the harm from destruction would be serious. These orders are always executed with strict procedural safeguards - typically an independent supervising solicitor, careful limits on what can be searched and seized, and a prompt return date for the defendant to challenge the order - given how intrusive they are.