American Cyanamid Co v Ethicon Ltd
The test for granting an interim injunction: a serious question to be tried, and the balance of convenience.
Facts
American Cyanamid held a patent for absorbable surgical sutures. It claimed that Ethicon was about to launch a competing suture in the UK that would infringe the patent, and it applied for an interim injunction to stop Ethicon from selling the sutures until the trial. The Court of Appeal refused the injunction, on the basis that American Cyanamid had not shown a strong prima facie case of infringement.
Legal principle
The House of Lords granted the interim injunction. Lord Diplock said that the claimant does not need to show a prima facie case. The court must first be satisfied that there is a serious question to be tried, meaning that the claim is not frivolous or vexatious. It must then consider whether damages would be an adequate remedy for either party and, if there is doubt, where the balance of convenience lies, taking into account all the circumstances, including the importance of preserving the status quo. These guidelines remain the basis for interim injunctions in English law.
Related cases on civil justice and procedure
- Anton Piller KG v Manufacturing Processes Ltd [1976] Ch 55
- Arkin v Borchard Lines Ltd [2005] EWCA Civ 655, [2005] 1 WLR 3055
- Barton v Wright Hassall LLP [2018] UKSC 12, [2018] 1 WLR 1119
- Biguzzi v Rank Leisure plc [1999] 1 WLR 1926
- Callery v Gray [2002] UKHL 28, [2002] 1 WLR 2000
- Churchill v Merthyr Tydfil County Borough Council [2023] EWCA Civ 1416
- Denton v TH White Ltd [2014] EWCA Civ 906, [2014] 1 WLR 3926
- Dunnett v Railtrack plc [2002] EWCA Civ 303, [2002] 1 WLR 2434
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