Interim injunctions in Jersey: American Cyanamid Plus

• The American Cyanamid test remains the standard test in Jersey for interim injunctions.
  
  
• However, a more exacting 'Cyanamid Plus' test may be applied in exceptional cases, particularly where the interim relief would effectively grant the final remedy or render a trial otiose, or where both sides risk comparable, hard to quantify harm. 
  
  
• Practical case management can be decisive, especially for time sensitive disputes such as those concerning restrictive covenants, where expedited proceedings may avoid the need to modify the standard test.

In Jersey, the primary test for obtaining an interim injunction (which is different to a freezing injunction¹) was established by the House of Lords in American Cyanamid Co v Ethicon Limited [1975] AC 396 (Cyanamid Test). 

The Cyanamid Test has been applied by the Royal Court of Jersey (Court) regularly. The plaintiff is required to sufficiently evidence the following:

• there is a serious question to be tried; 
  
  
• damages awarded at trial would be an inadequate remedy for the plaintiff; 
  
  
• damages would be an adequate remedy for the defendant if an injunction were granted to the plaintiff to which they were later found not to be entitled; and
  
  
• if damages would not be an adequate remedy for the defendant if an injunction were granted to the plaintiff to which they were later found not to be entitled, the balance of convenience with a view to avoiding the greater risk of injustice between the parties favours the plaintiff.

More than a serious question to be tried 

Whether there is a serious question to be tried does not require the plaintiff to show that it is more likely than not that it will succeed at trial². The Court has held that '[it] is not a demanding test'³, with the plaintiff typically being required to demonstrate that the claim has substance and is not frivolous or vexatious.

However, in State House Trust Company Limited (in its capacity as Trustee of the G2007 Settlement) & Ors v Friend Media Technology Systems Limited & Ors [2025] JRC 158, the Court considered two circumstances where an elevated – or more demanding - test might be applied which involves an assessment of the merits of the parties' substantive cases before trial (Cyanamid Plus Test).  

These are discussed in more detail, below. 

An injunction that determines the issue(s) in dispute

The Court was referred to Martin and Co (UK) Limited v Cedra Limited [2015] EWHC 1036 (Ch), which concerned, inter alia, an application for an interim injunction to enforce restrictive covenants that would have wholly or substantially expired before a trial had occurred.⁴ 

The parties in Martin agreed that if the interim injunction was granted it would have the practical effect of granting the substantive relief (i.e., there would then be no need for a trial). This resulted in the 'serious question to be tried' test being modified to encompass a review of the merits of the parties' respective cases as they appeared from the affidavit evidence.⁵

The approach in Martin appears to be consistent with that in Allfiled UK Ltd v Eltis and others [2015] EWHC 1300 (Ch)) where it was held that:

'... that the [Cyanamid Test] of a serious question to be tried is only to be departed from in extreme circumstances where a trial is rendered plainly and obviously otiose.'⁶

In State House, the Court did not agree that the granting of an injunction would determine all of the issues between the parties, distinguishing the circumstances from Martin. The Court therefore declined to apply the Cyanamid Plus Test and instead applied the Cyanamid Test. 

The Court also held that there were strong policy reasons why it should be cautious about assessing the merits of a claim at the interlocutory stage and on affidavit evidence alone. 

Difficulties in assessing financial compensation

The Court did note, however, that in circumstances where there is approximately equal damage not capable of being easily measured in financial recompense to both parties, it should consider the merits of the parties’ substantive cases which could 'swing the balance' as to whether an injunction should be granted.⁷

Conclusion

The application of the Cyanamid Plus Test requires specific circumstances which might not arise regularly. However, it remains a relevant consideration, particularly for those considering an application for an interim injunction which would be determinative of the relief ultimately sought. 

Where restrictive covenants are sought to be enforced, the speed at which the matter can be finally determined can often be in issue, as was the case in Martin. A potential option here would be for the matter to be heard as a cause de brièveté. The Court is empowered under its inherent jurisdiction to order an expedited procedural timetable and trial if it is satisfied that:

• the defendant will have a reasonable time to prepare their defence; and
  
  
• the matter is one of sufficient urgency to justify such an order.

Finally, it is worth noting that the Court will look closer at the merits of the parties' respective cases where there is approximately equal damage not capable of being easily measured in financial recompense. This could result in a similar outcome to the Cyanamid Plus Test being applied. 

_{1 A modified test is applicable when applying for a freezing order in Jersey. The plaintiff must show that (i) there is a serious issue to be tried (ii) there is a real risk of dissipation of the defendant's assets and (iii) it is just and convenient to grant the relief sought. 
 2 Dandara (Jersey) Limited v Clancy [2025] JRC 068 at [21].
 3 Ibid. 
 4 This can be a particular issue in employment cases, where employees have short restrictive covenants. In this situation the court must consider if the matter can be dealt with as a cause de brièveté, and if not it is likely to apply the Cyanamid Plus Test. 
 5 [16], referring to Lawrence David Limited v Ashton [1991] 1 All ER 385. 
 6 [78].  
 7 [29].}