Posted on 29/3/2019

Infringement by Equivalence in the Intellectual Property Enterprise Court

The new test of patent infringement is used in the IPEC for the first time.

On 26 February 2019 the Intellectual Property Enterprise Court (IPEC) handed down a judgement of patent infringement based on the relatively new, broader definition of infringement, in Marflow Engineering v Cassellie. This judgement confirms that the new test of infringement by equivalence is being used throughout the UK court system, and so it clearly needs careful consideration when considering patent infringement, no matter the value of the infringement.


In July 2017, the Supreme Court, the country’s highest court, handed down a judgement on patent infringement which significantly changed the concept of patent infringement in the UK, in Actavis v Eli Lilly ([2017] UKSC 48). Our article on the judgement can be found here. The judgement introduced the new test of infringement by equivalence. Therefore, acts which once would not have been considered infringing could now infringe a patent.

There are three questions to answer as part of the new test, but the key question is whether a variant (i.e. a product which does not infringe based on ‘normal infringement’, due to lacking features of a patent claim) achieves the inventive concept revealed by the patent. If it does, then the variant is likely to be found to infringe by equivalence.

In October 2018, the Court of Appeal, the second highest court, handed down a judgement which considered infringement by equivalence, in Icescape v Ice-World ([2018] EWCA Civ 2219). Our article on the judgement can be found here. The subject matter in this case was mechanical, rather than chemical as in Actavis v Eli Lilly, and so the judgement demonstrated that the new test applies across all patent disciplines.

With the test established and used in the two highest courts, we then expected to see it the infringement by equivalence test being considered in lower courts.

The IPEC is a first instance court specialising in Intellectual Property. The court typically deals with claims of infringement where the damages sought are less than £500,000 and has a cap on cost orders. Given infringement matters for many SMEs can fall below this level of damages, this court is often used by such companies.

The Judgement in Marflow Engineering v Cassellie

The patent in question claimed a method of installing an appliance, such as a shower. Marflow Engineering claimed that Cassellie’s marketing of a fixing plate used in the installation of showers and the like infringed the patent. The judgement found the patent to be valid, and so moved on to whether it was infringed.

The claimed method includes the steps of securing a mounting member, having a generally plate-like configuration body, on a wall at a mounting position where a part of a fluid pipe extends outwardly of the wall. An aperture in the mounting member receives part of the fluid pipe, and the fluid pipe is locked relative to the mounting member by tightening a locking element on a locking member. The body of the mounting member provides, in or thereon, the locking member.

Cassellie’s product was a plate with separate threaded pipes intended to extend through the plate in use. In use, each threaded pipe is attached to a further respective pipe in a wall. The threaded pipes could then extend out of the wall, and the plate could be secured against the wall and the threaded pipes locked in position relative to the plate by nuts on the threads of the pipe.

The threads on the pipes and nuts of Cassellie’s product were not considered to be locking members provided in or on the plate and locking elements which are tightened onto the locking member, and so the product was not considered to infringe the claim by ‘normal infringement’. The court therefore moved on to considering infringement by equivalence.

The inventive concept of the claimed method was considered to be the idea of using a plate (mounting member) to install a fluid-using appliance by securing the plate to the wall, receiving the fluid pipes extending out of the wall through apertures in the plate and then using a locking means to lock the pipes to the plate.

The method of using Cassellie’s product was found to achieve this inventive concept in substantially the same way as the invention. Therefore, the patent was found to be infringed.


As mentioned above, this judgement confirms that this new test is being used throughout the UK court system, and so is clearly a test which needs careful consideration when considering patent infringement, no matter the value of the infringement.

As mentioned in our previous articles, patent owners may welcome such decisions since it confirms that the scope of protection available in the UK can cover competing products that use the same inventive concept, even if they do not fall within the words used to define the invention.

On the other hand, the decision certainly confirms that it is it more difficult to ascertain the scope of protection based only on the patent at issue, which is bound to reduce legal certainty and/or increase the time and cost to provide an opinion on infringement.


We would reiterate our advice to revisit any infringement opinions given before the Actavis v Eli Lilly decision in July 2017 (and perhaps opinions produced shortly afterwards), as it is clear that that decision has wide application regardless of the technology concerned.

In particular, most opinions prior to the Actavis v Eli Lilly decision will only comment on infringement under a “purposive construction”, but now, having decided on non-infringement under a purposive construction, it is necessary to consider whether the patent might be infringed by “equivalence”.

If you are concerned about a competitor infringing your patent, or concerned about infringing your competitor’s patent please contact one of our attorneys.

Wilson Gunn