EPO Moves Closer to Unified Patent Court Approach as G1/24 Reshapes European Patent Claim Interpretation

A European patent’s protection depends not only on the words written in its claims but also on how those claims are interpreted in the context of the patent as a whole. A landmark decision by the European Patent Office (EPO) is bringing greater consistency to that process, with potential implications for patent applications, opposition proceedings and litigation across Europe.

In June 2025, the EPO’s Enlarged Board of Appeal issued decision G 1/24, ruling that patent claims must be interpreted with reference to the description and drawings when assessing whether an invention is patentable. The description and drawings must be consulted even when a claim appears clear when read on its own.

The decision brought the EPO’s approach closer to principles already applied by national courts and the Unified Patent Court (UPC), which handles certain patent disputes across participating European countries. Subsequent EPO appeal decisions in 2026 have continued to clarify how the ruling applies beyond novelty and inventive-step assessments.

For companies seeking patent protection in Europe, the development highlights the importance of drafting claims that work consistently with the technical explanation and drawings throughout a patent application.

What G 1/24 Changed in European Patent Practice

Before G 1/24, EPO appeal boards had developed differing approaches to whether a patent’s description and drawings should be consulted when interpreting claims during patentability assessments.

Some decisions treated the description and drawings as relevant primarily when the claim wording was unclear or ambiguous. This could produce a different interpretive approach from that used by courts considering the scope of protection or the validity of a patent.

The case arose from a referral concerning a patent application involving heated aerosol technology. The Enlarged Board of Appeal was asked to clarify the principles governing claim interpretation, including whether the description and drawings should always be considered.

Its answer established two central principles.

First, the claims remain the starting point and basis for assessing patentability. Second, the description and drawings must always be consulted when interpreting those claims for assessments under Articles 52 to 57 of the European Patent Convention (EPC).

The ruling does not mean that the description can simply replace the wording of a claim. Rather, the claims define the subject matter being assessed, while the description and drawings provide technical context that can inform the meaning of the claimed features.

This distinction is important because patent claims establish the boundaries of the invention for legal purposes, but their meaning may depend on how technical terms are used and explained within the patent document.

Why the Unified Patent Court Matters

The UPC began operating on June 1, 2023, creating a common judicial system for participating European countries to hear certain disputes involving European patents and unitary patents.

Its jurisdiction includes infringement proceedings and actions challenging patent validity, subject to the applicable rules and the status of the patent concerned.

In a February 2024 decision involving NanoString Technologies and 10x Genomics, the UPC Court of Appeal addressed how patent claims should be interpreted. The court stated that principles of claim interpretation apply to both infringement and validity assessments.

The EPO’s G 1/24 decision subsequently acknowledged that the UPC’s approach appeared consistent with the interpretation principles it adopted. The Enlarged Board also emphasised the importance of avoiding an EPO practice that deliberately diverged from the approach used by courts dealing with patents after grant.

The result is a stronger basis for consistency between the examination of European patent applications and later judicial proceedings.

However, the EPO and UPC remain separate institutions with different responsibilities. G 1/24 did not merge their procedures or make every aspect of their patent law identical. It aligned an important interpretive principle while leaving each institution to apply the relevant legal framework in its own proceedings.

How Patent Claim Interpretation Works

Patent claims describe the technical features for which an applicant seeks legal protection. Their interpretation can determine whether an invention meets patentability requirements or whether a particular product falls within the scope of a granted patent.

Consider a hypothetical patent claim describing a device with a “flexible support member.” The description may explain the material, geometry and role of that component, while the drawings show how it fits into the larger device.

Reading the phrase in isolation may leave several technically plausible meanings. Consulting the rest of the patent can help establish how a skilled person would understand the term in its specific technical context.

G 1/24 makes that contextual consultation a required part of interpreting claims for patentability assessments, rather than a step reserved for wording that initially appears ambiguous.

The claims nevertheless remain the starting point. The description and drawings help explain the claimed subject matter; they do not provide unrestricted permission to add features that the claims do not contain.

The decision also highlights the importance of clarity. Under Article 84 EPC, patent claims must be clear and concise and supported by the description. The Enlarged Board stressed that applicants and examiners should address genuine clarity problems through appropriate claim drafting and amendment.

What Changed in 2026?

The practical significance of G 1/24 has continued to develop through subsequent decisions of the EPO’s Boards of Appeal.

In March 2026, Technical Board of Appeal decision T 847/24 discussed how the principles established in G 1/24 should be applied. The board emphasised that a claim should not be interpreted in isolation and that the description, drawings and other claims may inform the meaning of its features.

The decision also addressed the implications of consistent claim interpretation across different legal assessments. The same interpretive approach may be relevant not only to novelty and inventive step but also to questions such as added subject matter, sufficiency of disclosure and the extent of protection.

This does not mean that every legal test has become identical. Each ground of challenge retains its own requirements. Rather, the meaning assigned to a claim should be established consistently when that meaning matters to the outcome of a proceeding.

These developments are particularly relevant to patent disputes in which the parties disagree over the technical meaning of a feature or whether the description supports a particular interpretation.

They also demonstrate that G 1/24 was not simply a statement about consulting additional documents. It has become a reference point for how patent claims should be interpreted consistently across different stages of the European patent system.

Implications for Patent Drafting and Prosecution

For businesses and inventors seeking protection in Europe, the decision reinforces the need to treat the patent application as an integrated technical and legal document.

Patent drafting typically involves defining the invention in the claims, explaining its technical operation in the description and providing drawings where necessary. G 1/24 makes the relationship between these elements particularly important.

Applicants should ensure that key technical terms are used consistently, that the description explains the claimed features and that the drawings support the technical relationships set out in the claims.

A poorly aligned description may create uncertainty over the meaning of a feature even if the claim appears straightforward at first glance. Conversely, a detailed and consistent explanation can help establish the intended technical context.

The ruling may also affect how patent attorneys approach prosecution, the process through which an application is examined and amended before grant. During examination or opposition, the description and drawings can become relevant to arguments about how a claim should be understood.

Nevertheless, the decision does not eliminate the need for precise claim language. Nor does it guarantee that the EPO and UPC will reach the same conclusion in every dispute. Differences can still arise because of distinct procedural rules, evidence, legal questions and the facts of an individual case.

What It Means for Patent Owners and Technology Companies

The move towards greater consistency has implications across industries that rely on patent protection, including biotechnology, pharmaceuticals, medical devices, electronics and advanced manufacturing.

For patent owners, interpretation can affect the strength of a granted patent and the ability to enforce it against competing products. For companies developing new technologies, understanding how claims may be interpreted can inform freedom-to-operate assessments, product design and the evaluation of potential infringement risks.

Investors and businesses assessing patent portfolios may also need to consider how the description and drawings support the scope of protection claimed. A patent’s commercial value depends not only on its existence but also on the legal strength and practical reach of its claims.

The impact will vary by case. G 1/24 does not automatically expand or narrow every European patent, and it does not guarantee a more favourable result for either patent owners or challengers.

Its broader significance lies in making the interpretive framework clearer and reducing the likelihood that different parts of the European patent system approach the same technical language according to fundamentally conflicting principles.

A More Consistent—but Still Evolving—European Patent System

G 1/24 marks an important step towards greater consistency between EPO patentability assessments and the approach taken by courts, including the UPC. Subsequent appeal decisions have begun clarifying how that principle operates across different legal questions.

The ruling preserves the central role of patent claims while requiring the description and drawings to be considered when determining their meaning. That approach places greater emphasis on the relationship between the wording of an invention and the technical context in which it is presented.

For innovators seeking protection across Europe, the practical lesson is straightforward: patent claims, descriptions and drawings must work together as a coherent whole.

The full effects of G 1/24 will continue to emerge as the EPO Boards of Appeal and the UPC develop their respective case law. Greater alignment is now an explicit objective, but consistency in individual cases will depend on careful drafting, sound legal reasoning and the facts of each dispute.

FAQs

1. What is EPO decision G 1/24?

G 1/24 is a June 2025 decision by the EPO’s Enlarged Board of Appeal. It established that patent claims are the starting point for assessing patentability and that the description and drawings must always be consulted when interpreting those claims.

2. How does G 1/24 relate to the Unified Patent Court?

The decision brought the EPO’s approach closer to claim-interpretation principles used by national courts and the UPC. It did not merge the institutions or make all their procedures identical.

3. Does G 1/24 mean patent descriptions can override claims?

No. The claims remain the starting point and basis for assessing the invention. The description and drawings provide technical context that can inform how the claimed features are interpreted.

4. Why is the decision important for patent applicants?

It reinforces the need for clear claims that are consistently supported by the description and drawings. This can affect examination, opposition proceedings and later disputes over patent validity or scope.

5. What did the EPO’s 2026 decisions add after G 1/24?

Subsequent decisions, including T 847/24 in March 2026, have clarified how the principles apply to different assessments. They emphasise contextual and consistent interpretation while preserving the distinct legal requirements of each ground of challenge.