20 April 2021

UK Patents Court Update – You must expressly plead equivalence at an early stage

Lord Justice Birss in a pre-trial review for Facebook Ireland Ltd v Voxer IP LLC [2021] EWHC 657 (Pat), has made it clear that a patentee wishing to rely on the doctrine of equivalents as part of its infringement case must say so at an early stage and must state its position in its Particulars of Infringement.


Following the landmark decision in Actavis v Lilly 2017, the doctrine of equivalents has become a part of the UK patent litigation landscape. It has the potential to extend the scope of a patent’s claims to include variants beyond a purposive interpretation, and we have commented on this in our coverage of the Actavis V Lilly decision here and here.

This new guidance arises because patent pleadings are often short, and there was a complaint about late amendment to add in the equivalence argument. Uncertainty between parties is discouraged in patent litigation and this decision confirmed clarity is needed at an early stage, with the parties considering the ‘Actavis questions’ as soon as possible and not just when preparing their expert evidence.

The present case started as a patent revocation action brought by Facebook Ireland against Voxer under the Shorter Trials Scheme (STS). The STS (previously a pilot scheme) became permanent with effect from 1 October 2018, and aims to achieve shorter and earlier trials at a reasonable and proportionate cost.

Voxer counterclaimed that certain features used by the live-streaming platforms Facebook Live and Instagram infringe its patent. Following a pre-trial review (PTR), Lord Justice Birss made it explicitly clear that although the case was to proceed under the STS, he was not taking that into account and was looking at the issue that this was simply a case proceeding in the Patents Court under Civil Procedure Rule (CPR) 63.

Lord Justice Birss’ decision

In this case, Voxer had sought to amend its Particulars of Infringement based on the doctrine of equivalents. However, Facebook objected to one of Voxer’s proposed amendments on the grounds that Voxer should have originally pleaded its case under the doctrine of equivalents, including the identification of the inventive concept.

The Judge stated that any case based on the doctrine of equivalents involves assertions of facts that will be distinct from general questions arising in relation to infringement on a normal construction of the claims. Therefore, patentees relying on the doctrine of equivalents must ensure that their Particulars of Infringement contain a statement by reference to each relevant claim feature (and claim), that equivalence is relied on. The Judge noted that it is not a serious burden to patentees to have to do this, and certainly no more of a burden on the party challenging validity when pleading its case on insufficiency or added matter.

In providing his guidance, the Judge concluded that he did not need to decide if all the details should be pleaded out fully from the outset, or if it is necessary for the inventive concept to be characterised in the Particulars of Infringement. However, the Judge was clear that in his view in the normal multitrack in the Patents Court it would be appropriate at the onset of the claim or at least in the Particulars of Infringement for the patentee to articulate its case on inventive concept and the other aspects of the test set out in Actavis.

In reaching his decision, the Judge referred to CPR 63(6) and Practice Direction 63 paragraph 4.1, which both set out what must be pleaded in the Particulars of Infringement. The Judge opined that although Part 63 and the corresponding Practice Direction do not explicitly mention equivalents, that does not mean that reliance on equivalents should not be stated in the pleadings.

The Judge explained that CPR 63 and the corresponding Practice Direction “function in an overall context governed by CPR 16 about Statements of Case in general.”  The Judge then made reference to CPR 16.4(1)(a), which requires that a Particulars of Claim must include “a concise statement of the facts on which the claimant relies.” In the Judge’s opinion, a case based on the doctrine of equivalents inevitably involves an assertion or assertions of fact that are distinct from the general questions of fact arising in relation to infringement on a normal construction. This is supported by the first and the second Actavis questions which necessarily include such distinct issues of fact. Therefore, in the Judge’s opinion a proper application of CPR 16.4 requires equivalence to a particular claim feature to be pleaded.

The Judge went further to explain that if a patentee were to make such an assertion that cannot later be explained or supported by a claim chart or future statement of case, then the assertion and reliance on equivalence will undoubtedly be struck out.


Lord Justice Birss was unequivocal in stating that a reliance on the doctrine of equivalents must be pleaded. The Judge’s guidance makes it clear that patentees wishing to rely on the doctrine of equivalents as part of a case alleging patent infringement must consider their strategy at an early stage and state their position in their Particulars of Infringement, irrespective of whether the case is being heard in the Patents Court, Intellectual Property Enterprise Court (IPEC) or under the STS.

The Judge was clear that patentees should state any reliance on the doctrine of equivalents in their Particulars of Infringement, irrespective of the forum where the claim was brought. The Judge acknowledged that while it may be appropriate for patentees to articulate their case on inventive concept in their Particulars of Infringement in cases proceeding in the High Court, this may be different in the IPEC or under the STS, where it may already be required. Certainly in the IPEC, following the decision in Kwikbolt v Airbus [2019] EWHC 2450 (IPEC), it would appear that the inventive concept should be articulated at least by the time that the case management conference takes place.

The High Court’s decision can be read here.