American Cyanamid Case: The Four-Stage Test for Interim Injunctions

The American Cyanamid test is the four-stage framework English courts use to decide whether to grant an interim injunction while a case is still being fought out. Set down by the House of Lords, it asks the judge to work through a serious question to be tried, the adequacy of damages, the balance of convenience, and, as a last resort, the status quo.¹

Why the Test Replaced the Old Standard

Before American Cyanamid, an applicant had to show a prima facie case, meaning they had to persuade the judge at the outset that they were likely to win the whole trial. That pushed courts into deciding the merits before the evidence was ready.

The House of Lords rejected that approach. Judges were told to stop weighing the evidence in depth at the interim stage and instead work through a structured assessment of risk and fairness to both sides.¹

Stage One: Is There a Serious Question to Be Tried?

The first hurdle is deliberately low. The applicant only needs to show a real prospect of succeeding at trial. The judge does not resolve conflicting evidence and does not try to answer difficult points of law at this stage.¹

The point of keeping the threshold low is to filter out frivolous claims without holding a mini-trial before both sides have completed formal disclosure.¹

Stage Two: Would Damages Be an Adequate Remedy?

If the claim clears the first stage, the court asks whether money would put things right. If the applicant could be fairly compensated in cash after winning at trial, the injunction will normally be refused now.²

The same question runs in reverse. The applicant is usually required to give a cross-undertaking in damages, a formal promise to compensate the defendant for losses caused by an injunction that later turns out to have been unjustified. If the court doubts the applicant can honor that promise, it may demand additional financial security.³

Stage Three: Where Does the Balance of Convenience Lie?

The balance of convenience is the heart of the exercise. The judge compares the hardship each side would face under either outcome and looks for the option that risks the least harm that money cannot fix.⁴

Practical factors a court may weigh include:²

Whether a business might be forced to close or lose its position in the market.
The risk of significant disruption to day-to-day operations.
The effect on employees or on existing agreements with third parties.

Where the harm to the defendant from granting the order outweighs the benefit to the applicant, the injunction is usually refused.⁴

Stage Four: Preserving the Status Quo

When the hardships look roughly equal, the court falls back on the status quo. Described in the case law as a counsel of prudence, this step encourages the judge to keep things as they stood before the dispute arose, so no major change is locked in before trial.¹

In practice, that tends to favor the party defending the existing state of affairs over the one seeking to disturb it. It gives the court a workable tiebreaker when the earlier stages leave the scales even.¹

1
Parliament.uk. Cream Holdings Limited and others v. Banerjee and others
2
Parliament.uk. Correspondence with Ministers May to October 2007 – Section: 12. Injunctions
3
Justice.gov.uk. Civil Procedure Rules Part 25 – Section: Form of order (rule 25.9)
4
Parliament.uk. Her Majesty’s Attorney General v. Punch Limited and another