High Court Endorses Seven Principles for Securing Precautionary Injunctions

Injunctions are typically sought by parties after wrongdoing has already taken place. However, English courts may grant a ‘quia timet’ – or ‘precautionary’ – injunction to prevent an actionable wrong from being committed.   In University of Brighton v. Persons Unknown Occupying Land,[1] the High Court of England and Wales granted a final injunction preventing protesters from occupying certain areas of the claimant’s executive administration office. This judgment provides a useful restatement of the principles applied by the courts when determining whether to award a precautionary injunction.


On 25 May 2023, ‘persons unknown’ broke into the offices of the university’s executive administration office and barricaded themselves inside. They also accessed the roof of the building, displaying banners that publicised their protest against the possibility of redundancies taking place amongst staff at the university. On 30 May 2023, the claimant was granted an interim injunction which required the ‘persons unknown’ to vacate the premises. Even after they were notified about the interim injunction, the protesters remained, only leaving six days later (and not necessarily because of the existence of the order). The claimant then applied for a final injunction to restrain and prevent future acts of trespass.

The High Court’s decision

Until recently, courts considering applications for precautionary injunctions would apply a two-stage test:

  • Is there a strong probability that, unless restrained by an injunction, the defendant will commit a wrong against the claimant?
  • If the defendant committed that wrong, would it cause irreparable harm?

In Boyd and Another v. Ineos Upstream Limited and Others,[2] the Court of Appeal addressed the issue of making precautionary injunctions against ‘persons unknown’. Noting that it should be inherently cautious about granting injunctions in these cases since the reach of such an injunction is necessarily difficult to assess in advance, the Court of Appeal set out six requirements to be met:

  • There must be a sufficiently real and imminent risk of a tort being committed. This is equivalent to the first limb of the two-stage test noted above.
  • It must be impossible to name the persons who are likely to commit the tort unless restrained.
  • It must be possible to give effective notice of the injunction and for the method of service to be set out in the order.
  • The terms of the injunction must correspond to the threatened tort and not be so wide that they prohibit lawful conduct.
  • The terms of the injunction must be sufficiently clear and precise to enable persons potentially affected to know what they must not do.
  • The injunction should have clear geographical and temporal limits.

In the present case, the High Court applied a combination of the two- and six-part tests to formulate seven principles. In doing so, it stated that, while the second limb of the two-part test was not applied in Ineos, it is essential not to be misled by the context of that case, in which it was not necessary to consider that ‘essential’ element.   In respect of the first principle, the High Court acknowledged that there are slightly different formulations, with some authorities requiring a ‘sufficiently real and imminent risk’ and others requiring a ‘strong probability’ of a tort being committed to justify the relief. The High Court did not express a preference for either formulation, commenting that the difference reflected the fact that there is ‘no fixed or absolute standard for measuring the degree of apprehension of a wrong which must be shown to justify quia timet relief’. It went on to note that the graver the likely consequences of the risk of wrongdoing, the less it would consider the application as premature, provided there is ‘at least some real risk of an actionable wrong’.
Applying these principles, the High Court found as follows:

  • The High Court considered both the fact that the underlying dispute about redundancies that prompted the protest was still live and the past conduct of the ‘persons unknown’ in flagrantly ignoring the interim injunction in ultimately finding that the risk was sufficiently real and imminent – or that there was a strong probability of it.
  • It was impossible to name the persons likely to commit the tort unless restrained.
  • It was possible to give effective notice of the injunction and for the method of such notice to be set out in the order (as had happened with the interim injunction order – although no details of the method were given in this judgment). 
  • The terms of the injunction corresponded to the threatened tort and were not so wide that they prohibited lawful conduct, because the injunction would not affect the right of any student to enter the premises for education- or university administration-related business. That’s because ‘occupying’ was defined in the order as ‘remaining in the Premises by barricading oneself within the Premises and refusing to vacate’, which clearly did not encompass lawfully entering the premises.
  • The terms of the injunction were sufficiently clear and precise to enable persons potentially affected to know what they must not do. Interestingly, the judge dismissed the use of the words ‘with the purpose of protesting’ from the order, finding that it was preferable to restrict the definition of prohibited acts to the acts themselves (i.e., barricading and/or refusing to vacate the premises), rather than their purpose.
  • The injunction had clear geographical and temporal limits, as the ‘premises’ were defined and the temporal limit was set to six months (as the redundancy-related issues were likely to be resolved within six months).
  • As to the gravity of the potential harm, the High Court took account of:
  • The material health and safety risk to both the protesters and others given the way that the protesters had previously sealed themselves within the 8th floor of the building with no easy means of escape.
  • The potential cost of further repairs and legal costs of obtaining another interim injunction which, in the circumstances, might be better spent providing education and/or mitigating the financial position of the claimant about which the protesters were complaining. (While theoretically compensable in damages, the High Court noted that – in reality – these costs were irrecoverable.)
  • Reputational damage nationally and internationally that, if resulting in a drop in student numbers, could cause irreparable financial harm. It therefore concluded that the potential harm was sufficiently grave and irreparable to justify the granting of the injunction.


This is a timely decision: The marked increase in protests on private land will likely precipitate an increase in applications for precautionary injunctions. But trespass cases are, of course, just one context in which to use what can be an invaluable tool to avoid suffering harm. While the judgment clarifies that it is still essential that applicants for a precautionary injunction demonstrate that the resulting harm would be irremediable in damages, it helpfully confirms that in assessing the gravity of likely harm, the claimant’s inability to recover its costs from the defendant may be sufficient to demonstrate that damages are an insufficient remedy.  

[1] [2023] EWHC 1485 (KB).[2] [2019] EWCA Civ 515.


Ollie McGlashan