What if a competitor has a patent that protects one thing on paper but in reality is used much more broadly to tackle infringements by others? Until recently this was something that could happen in Europe, but that has now changed thanks to a landmark case by patent attorneys Marcel Kortekaas and Thomas Remmerswaal.What exactly has changed?
The Enlarged Board of Appeal, the European Patent Office’s highest legal body, has ruled that a patent must always be assessed as a whole: not just the literal text of the claims, but also the description and drawings. That may sound technical, but it makes a world of difference.
The Angora cat paradox
As patent scholar Mario Franzosi put it, patents can behave like Angora cats. They squeeze through a narrow cat flap, then fluff up to twice their size once inside. Some patents slip through the grant procedure with narrow claims, then expand their protection through broad definitions in the description. Small for grant, big for infringement. Handy for the patent holder, but hardly fair.
Trying to claim more protection
Let’s use colour as an example. A patent consists of claims (what you want to protect), a description (which explains the claims in more detail) and figures (drawings). A claim may state that the product is black. During grant, the EPO assesses whether black products are new and inventive. Suppose a competitor finds an older document describing dark grey. Black is still new, even though it looks a lot like dark grey.
But what if the description says black also covers dark grey, dark blue and dark purple? Then the patent holder can go after dark blue products in infringement proceedings before the national court or the new Unified Patent Court (UPC). The patent system (rightly) lets protection reach a little beyond the literal claim, so competitors can’t easily get around it.
But before Marcel and Thomas’s case, dark grey, dark blue and dark purple were sometimes ignored when the patent was assessed, even though the patent protected them and dark grey was already known. The patent was granted for “black” but protected much more.
New case law
In June 2025, the Enlarged Board of Appeal put a stop to that. It ruled that the description and figures must always be taken into account when assessing novelty and inventive step, not just the literal text of the claims. That’s fair: a patent should be judged the same way at every stage. You shouldn’t be able to read your patent narrowly to get it granted, then broadly to go after infringers.
This is the first time it has been confirmed that the description and figures must always count, including at grant. That matters, because the ruling now applies to every similar case. It strengthens legal certainty for third parties in all EPC countries, throughout the life of a patent.
The Diamond Standard
At EP&C, we’ve already nicknamed the ruling the ‘Diamond Standard’: a step up from the ‘Gold Standard’ of earlier case law, and a nod to its strength and brilliance.
