In a case concerned with an environmental protest, the UK Supreme Court has provided clarity on the test for joint liability[1] in IP infringement (and indeed in all tort cases).

In Sea Shepherd UK (Appellant) v Fish & Fish Ltd (Respondent)[2] the UK Supreme Court reversed a decision by the Court of Appeal holding the appellant UK charity liable to the respondent as a joint tortfeasor.  Whilst the Court was divided as to the application of the law to the particular facts of the case, the Court agreed unanimously on the legal test to be applied to establish liability for joint tortfeasorship. In the UK, infringements of intellectual property rights are torts.  This case gives a useful summary of the law relating to joint liability in tort (and thus in IP infringement cases), and serves as a useful reminder that joint tortfeasorship is highly fact sensitive, and will always depend on the particular circumstances of the case.


The appellant, SSUK, is a UK registered charity.  Its parent is a US marine conservation charity, controlled by a Canadian individual. SSUK and its US parent had been involved in a campaign to “intercept and oppose the illegal operations of bluefin tuna poachers”. The respondent, Fish & Fish Limited, operates a fish farm in the Mediterranean. Fish & Fish brought proceedings against SSUK for damages it suffered as a result of an incident in 2010.  On the day in question, Fish & Fish had been transporting a catch of tuna in fish cages when their vessels were attacked by a vessel belonging to SSUK.

The appeal before the Supreme Court arose from a preliminary issue as to whether the incident was directed and/or authorised and/or carried out by or on behalf of SSUK, and whether SSUK was liable for any damage sustained by Fish & Fish.  At first instance, Hamblen J held that SSUK’s assistance in the incident was of minimal importance and that SSUK was therefore not liable in damages to Fish & Fish as a joint tortfeasor. This decision was reversed by the Court of Appeal, who held that SSUK’s activities were sufficient to establish accessory liability in tort. SSUK appealed to the Supreme Court.  The main issue before the Supreme Court was whether SSUK’s contribution to the campaign, and thus to the tort, was of minimal importance, as had been held at first instance.  If SSUK were found not to have provided sufficient assistance in furthering the common design to commit the tort of deliberately damaging or destroying property of other persons at sea without their consent, then the claim against SSUK would fail, regardless of whether a common design between SSUK and its US parent were proven.

By a majority decision (Lords Sumption and Mance dissenting), the Supreme Court allowed the appeal and held that the judge at first instance had been entitled to conclude that SSUK’s contribution to the tort was de minimis, and not substantial enough to establish joint tortfeasorship.

The test for joint tortfeasorship

The Supreme Court was in unanimous agreement on the test for joint torfeasorship.  Lord Sumption noted [at paragraph 40] that “In both England and the United States, the principles have been worked out mainly in the context of allegations of accessory liability for the tortious infringement of intellectual property rights.  There is, however, nothing in these principles which is peculiar to the infringement of intellectual property rights.

He summarised the test as follows:

A defendant will be jointly liable for a tort if:

  1. he has assisted the commission of the tort by another person;
  2. it is pursuant to a common design; and
  3. an act is done which is, or turns out to be, tortious.

The court was agreed that it was not enough to show that a defendant did acts which merely facilitated the commission of the tort by another person.  Neither is it enough that the defendant knew his acts would facilitate the commission of the tort. Rather, it must be shown that both parties combined to do or secure the doing of acts which constituted the tort.  In other words, there must be a shared intention to commit the tort.

The majority of the court agreed that the assistance must be substantial, and not de minimis – merely trivial assistance is not enough to bring a defendant within the scope of the tort as a joint tortfeasor.  On the particular facts of the case, the majority view was that SSUK’s acts had been on a sufficiently small scale for SSUK to escape liability as joint tortfeasor. However, Lords Sumption and Mance disagreed, and they stated that SSUK’s participation in fundraising for the campaign had been enough to establish accessory liability.


The Supreme Court unanimously reaffirmed the law of joint tortfeasorship. Whilst the court was in agreement that the assistance provided by SSUK had been provided pursuant to a common design, the majority held that that assistance did not overcome the substantiality hurdle. The test for establishing liability for joint tortfeasorship is a matter of judgment, depending on the individual facts of the case.