The leading Supreme Court case of Actavis v Eli Lilly [2017] UKSC 48 introduced a doctrine of equivalents into UK patent law for the first time in many years. Since then, the Court of Appeal has given further guidance on this doctrine in Icescape Limited v Ice-World International BV & Ors [2018] EWCA Civ 2219 and there have been several cases post Icescape from the High Court which have applied the new approach. In November 2019, the Patents Court handed down another judgment, Excel-Eucan Limited v Source Vagabond Systems Limited [2019] EWHC 3175 (Pat) in which infringement was found under this doctrine.

Excel developed an ammunition bag for holding linked rounds of ammunition, known as the “Link-Tail”, which was protected by a patent, GB 2 489 116 (GB 116). Source developed its own bag – the “2017 bag” – and sought a declaration of non-infringement of GB 116. As validity of GB 116 was already being challenged in the UK IPO, the parties asked the court to assume the validity of GB 116 for the purpose of these proceedings.

An “openable closure”, namely a zip, was an integer of all independent claims of GB 116. The 2017 bag did not feature a zip, or any form of “openable closure”. Excel accepted that the 2017 bag did not fall within the claims as a matter of normal interpretation, but argued that the 2017 bag constituted an immaterial variation of, or was equivalent to, the invention disclosed by GB 116. Accordingly, the doctrine of equivalents was engaged.

Having accepted that the 2017 bag did not fall within the “normal interpretation” of the claims (as required by Actavis), Her Honour Judge Melissa Clarke applied the reformulated Improver questions, as outlined by Lord Neuberger in Actavis.

1. Does the variant achieve substantially the same result in substantially the same way as the invention? HHJ Clarke determined that the 2017 bag achieved substantially the same result as the Link-Tail, as she held the inventive concept (which she also referred to as “the clever bit”) to be the “plug and play” aspect of the ammunition bag. This meant that when the firearm was in use, the linked round could be fed from the bag into the firearm without the need to first remove the linked round from the bag. She rejected Source’s argument that the invention should be determined by reference to the patent itself and the claims, which all required an “openable closure”. HHJ Clarke did not agree that loading the bags vertically without an openable closure, as opposed to horizontally through the openable closure, meant that the result was achieved in a substantially different way – the different methods of loading were held to be “no more than a matter of convenience and preference…and a substantially similar way of working the invention”. The figures of the patent also did not disclose how the linked round was loaded in the Link-Tail, and the claims could have equally applied to horizontal or vertical loading.
2. Would it be obvious to the person skilled in the art, reading the patent at the priority date, but knowing that the variant achieves substantially the same result as the invention, that it does so in substantially the same way as the invention? HHJ Clarke determined that the skilled user would consider it to be obvious that the 2017 bag utilised a method of loading which did not require an openable closure, and that vertical loading could be used in the Link-Tail without utilising the openable closure.
3. Would such a reader of the patent have concluded that the patentee nonetheless intended that strict compliance with the literal meaning of the relevant claim(s) of the patent was an essential requirement of the invention? For the reasons given above, HHJ Clarke was satisfied that the skilled person would not have concluded that the openable closure was an essential requirement of the invention.

This case confirms that the new approach taken by English Patents Courts to the issue of equivalence by immaterial variants is quite generous to patent holders. Rather than focussing on the language of the claims, parties now need to focus on the inventive concept of the patent which, at least sometimes, might not be so easy to ascertain. Further guidance on this issue from higher courts would in the author’s view, be highly desirable.


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  1. The writer thinks that “further guidance” from the court of appeal would be “highly desirable”. Me too.

    As far as I am concerned, the task of a claim is to define the subject matter for which protection is sought, and that matter, for which protection is sought, is an “inventive concept”. If the courts are now going to ignore the claim, or at least slip its leash and untether the concept from the claim, and instead turn to the description and drawings to divine the governing “inventive concept” the subject of the patent, why should we patent attorneys bother to write any claims at all? This line of jurisprudence is taking back to the days, centuries ago, when patents did not include any claims. There was a good reason to impose on drafters the task of defining, in a claim, what was the inventive concept for which protection was being sought. the reason? Legal certainty.

    I am peeved, that Lord Neuberger, in striving to bring into English law a Doctrine of Equivalents in order to align English law on patent infringement with that of mainland Europe, has succeeded in widening the gap between the jurisprudence in England and that of The Continent. The claims are the same, all over Europe. What infringes them should be the same, all over Europe. Otherwise, business loses a degree of certainty and so is less confident, less inclined to invest in new technology.

    The Law of Unintended Consequences triumphs, yet again.

  2. I quite agree Max. Did the judge have the protocol to Article 69 in front of her when she wrote this decision?

  3. I can only but agree with Max Drei.

    In its quest of getting read of the disastrous Improver decision, Lord Neuberger has managed to fall in the opposite excess. This is even more so, that he referred to equivalents in Art 2 of the Protocol on interpretation of Art 69EPC, whereby the protocol fails to define what an equivalent should be. This had been proposed by the EPO, but was not accepted by the Diplomatic Conference.

    In Improver the claims were given their literal meaning, hence contrary to the rest of Europe, infringement was denied. In Actavis/Ely Lilly the claims are reduced to a kind of vaporous guideline whereby the actual protection conferred extends to what the patent proprietor has contemplated after filing of its application.

    One should not forget that the only way to implement the invention in the original application was with pemetrexed disodium. Nothing else had been contemplated at the time by the applicant. He just wanted a quick grant for pemetrexed disodium. It is only years later that the proprietor realised that other salts were usable for the purpose. No effort whatsoever beside a wishy washy introduction of the description could at the time provide any support for the later claim of the applicant.

    Actavis/Ely Lilly has certainly not improved the possibility of a reasoned FTO statement. The later decisions, and especially the present one, have made things even worse.

    But it is not infrequent, that one excess is replaced by the opposite one.

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