The Court of Appeal has held that a patent for a mobile ice rink lacking priority was invalid, and that threats made by the patent owner were unjustified; and, for the first time after Actavis v Eli Lilly, considered the scope of protection of a patent claim when assessing infringement by equivalents.


The scope of patent claims is determined in accordance with Article 69 of the European Patent Convention 1973 (EPC) and the Protocol on the Interpretation of Article 6, which aim to provide a balance between fairness to the patentee and giving the public reasonable certainty as to what those claims cover.

In Actavis v Eli Lilly, the Supreme Court considered the scope of protection of a patent claim when assessing infringement, and reformulated the law relating to infringement by immaterial variants([2017] UKSC 48).

In earlier case law the correct approach had been to look at the purpose underlying the claim rather than the literal construction of the words on the page (CatnicComponent Ltd v Hill & Smith Ltd [1982] RPC 237).

Section 70(2) of the Patent Act 1977 (section 70(2)), which sets out the defence of justification, requires the defendant to identify the infringed claims and to prove that the acts in question are infringing acts.


IW owned a European patent for a cooling system for a mobile ice rink.

IW's sales and marketing director sent threatening letters to IS and a large number of its customers or potential customers about the system it used for its mobile ice rink.

IS sought damages for groundless threats of patent infringement, a declaration of non-infringement and an order that IW's European patent be revoked. IW counterclaimed for infringement.

The High Court held that the patent was invalid because of prior use because IW could not rely on a priority document to maintain its earliest priority date. It held that the patent had not been infringed by IS and that IW had not successfully established the defence to the admitted threats under section 70(2). IW appealed.


The court upheld the decision of the High Court that the patent was invalid and IW did not have a defence to its admitted threats, but it reversed the non-infringement decision.

The patent was invalid over a prior disclosure unless it was entitled to the earliest claimed priority date. This involved interpreting the meaning of "same invention" in Article 87(1) of the EPC. The priority document as a whole had to disclose matter that effectively gave the skilled person essentially the same information as that which was the subject of the claim whose priority was in question. The priority document was read through the eyes of the skilled person, equipped with the common general knowledge, used for the purpose of interpreting the disclosure of the priority document and placing it in context, but not for supplementing that disclosure or adding what might seem to be an obvious further feature.

The key novel and inventive feature of the claimed invention was the use of joint elements, which enabled the folding of the unit to take place, and the skilled person would readily appreciate that one element of the kind depicted in the priority document could be joined to another to increase the width of the ice rink. However, there was no express or implicit disclosure in the priority document of two such elements joined together or of some other features of the patent claims and these features could not be derived directly and unambiguously, using common general knowledge, from the priority document as a whole. The patent was not entitled to priority and was therefore invalid.

In relation to infringement, the court applied Actavis. Initially the court had to determine the whether the variant infringed the claim as a matter of "normal interpretation": there was no doubt that this involved purposive interpretation It then had to consider whether it nonetheless infringed because the variation from the invention was immaterial. If the answer to either issue was "yes", there was an infringement; otherwise, there was not. To assess whether there was infringement by an immaterial variant the following questions had to be considered:

  • Firstly, the variant did achieve substantially the same result in substantially the same way as the invention, that is, the inventive concept revealed by the patent. Even though the IS system had some differences, it satisfied the aims of the patent. There had to be regard to the problem underlying the invention and the patent's inventive core. The inventive core of the patent was the provision of the joint member which formed a flexible, fluid tight connection between the rigid pipe sections and allowed the connected pipe sections to fold relative to one another for the purposes of transportation. This feature made the patented system different from the conventional systems which formed part of the common general knowledge.
  • Secondly, it would have been entirely obvious to the skilled person that, so far as the inventive core of the patent was concerned, the IS system achieved substantially the same result as the invention and did so in substantially, indeed precisely, the same way.
  • Thirdly, here there was no reason why the skilled reader would have thought that strict compliance with these integers was an essential requirement of the invention. The fact that the language of the claim did not cover the variant was not enough to justify holding that IS did not satisfy this question. It had to be considered whether the additional claim integers not found in the IS system were an essential part of the invention in light of the inventive concept and inventive core of the patent.

So, the IS system fell within the scope of the patent protection and would have infringed had the patent been valid. IW's defence in relation to unjustified threats would also have failed.

This decision is important as it is the first time the Court of Appeal has considered the effects of Actavis. In Actavis, the alleged infringement included an equivalent of one or more of the integers of the claim. Here the IS system did not contain two integers of the main patent claim at all. The High Court had held that there was no infringement because that would have required the language of the claim to be ignored and would involve replacing one integer with either nothing at all or with functional language. The Court of Appeal held that the absence of the two integers was irrelevant to the issue of infringement by equivalents as these were inessential parts of the invention. So, arguably the Court of Appeal could be said to be applying the pre-Catnic "pith-and-marrow" doctrine of infringement. Here the application of the Actavis principles did not cause difficulty as the inventive concept of the patent was clear. Other cases may be more problematical, and how to apply Actavis to validity issues and inventive variants remains unclear.

Case: Icescape Ltd v Ice-World International BV and others [2018] EWCA Civ 2219.

First published in the December 2018 issue of PLC Magazine and reproduced with the kind permission of the publishers. Subscription enquiries 020 7202 1200.