Written by: Caleb Gilliam-Scott
The UK Supreme Court’s decision in Emotional Perception AI Ltd v Comptroller General of Patents, Designs and Trade Marks [2026] UKSC 3 marks a major shift in UK law on patent exclusions for computer-implemented inventions and, in particular, the “computer program … as such” exclusion.
It does so by decisively moving away from the Aerotel framework that has governed UK practice for nearly two decades and aligning UK interpretation of Article 52 EPC with the approach of the European Patent Office (EPO) Enlarged Board in G 1/19.
The case is also notable for its treatment of artificial neural networks (ANNs): the Court held that an ANN is, in substance, a program for a computer (and not hardware), but that this does not necessarily mean a claim involving an ANN is excluded from patentability. The real work is pushed into a new “intermediate step” aimed at filtering eligible technical contributions before assessing novelty and inventive step.
Background and procedural history
The appellant, Emotional Perception AI Ltd, sought a patent for a system/method using an ANN to recommend media files (music, video, text) predicted to produce a similar emotional response to a file the user likes.
The UKIPO Hearing Officer refused the application relying on the statutory and EPC exclusions for “programs for computers … as such”. The High Court allowed the appeal (which we previously reported here), holding that an ANN is not a program. The Court of Appeal reversed, reinstating the refusal under Aerotel. The case reached the Supreme Court raising three issues: whether Aerotel should still be followed; whether an ANN is a “program for a computer”; and whether the claims were excluded in their entirety.
The Supreme Court’s key holdings
- Aerotel should no longer be followed
The most legally consequential part of the decision is Issue 1. The Supreme Court held that the Aerotel four-step test should be abandoned because it is inconsistent with the EPC as authoritatively interpreted by the EPO Enlarged Board in G 1/19. The Court emphasised the strong policy and interpretive imperative for UK courts to seek uniformity with the EPC and EPO jurisprudence, especially where the Enlarged Board has spoken, unless clearly wrong or outside reasonable disagreement.
The Court accepted the central EPO criticism: Aerotel wrongly collapses the distinct EPC requirements (invention/technical character, novelty, inventive step, industrial application) by focusing on “contribution to the known art” at the exclusion stage, thereby importing novelty/inventiveness considerations into the threshold question of whether there is an “invention” at all under Article 52(2) EPC. In the Supreme Court’s view, Article 52(2) EPC is concerned only with whether the claim is an “invention”, and that inquiry should be kept separate from novelty and inventive step, which are dealt with later under Articles 54 and 56 EPC. Aerotel’s steps 2 to 4 cannot be reconciled with that structure.
The replacement approach is to adopt the approach taken in G 1/19 and Comvik’s second paragraph (which relate to the EPO “problem and solution” methodology for inventive step).
Importantly, the Court rejected the argument that aligning with G 1/19 forces UK law to abandon the Pozzoli approach to inventive step or adopt the EPO problem-solution approach wholesale. UK law may retain its inventive-step methodology, but must incorporate an intermediate filtering step.
- An ANN is a “program for a computer”
On Issue 2, the Court held that an ANN is not hardware but an abstract model: a structure performing mathematical operations (weights, biases, activation functions) that can be implemented on many forms of hardware (conventional computers, neuromorphic hardware, FPGAs).
The Court then held that “computer” should not be confined to conventional digital computers with a CPU, because the EPC must accommodate technological change (including analogue and quantum computers). Correspondingly, “program” should be understood broadly as a set of instructions capable of being followed by a computer of any kind to produce desired manipulations of data. On that basis, the ANN – taken as a whole, including topology, weights/biases and activation functions – constitutes a set of instructions to manipulate data and achieve a desired result, and therefore is a “program for a computer” within Article 52(2)(c) EPC.
- The claims were not excluded as “a program … as such” – but the case is remitted
Although ANNs qualify as computer programs, the Court held that under the “any hardware” approach, claims that involve technical means (hardware) have technical character and clear the low “invention” hurdle: the ANN must run on hardware; and the claims also referenced a database, network, and user device – all technical means. Accordingly, the claims were not excluded under Article 52(2)(c) and (3) EPC as a computer program “as such”. The UKIPO was wrong to refuse on that basis.
However, the Court did not decide whether the claims are valid overall. Instead, it stressed that the key next exercise is the “intermediate step” between eligibility (Article 52) and novelty/inventive step (Articles 54-56), which filters out features that do not contribute to, or interact with, the technical character of the invention viewed as a whole. The case was therefore remitted to the UKIPO Hearing Officer to apply that intermediate step and then assess novelty and inventiveness
Implications for Aerotel and UK practice
The immediate implication is straightforward: Aerotel’s four-step framework is no longer the governing approach in the UK for Article 52 EPC exclusions. That is a seismic change for UKIPO examiners and practitioners trained on Aerotel. While claim construction remains foundational, “identifying the contribution” and asking whether it falls within excluded subject matter is no longer the correct way to determine whether a claim is an “invention”.
More structurally, the case re-sets UK law into a three-stage analysis for computer-implemented inventions:
- Eligibility under Article 52 EPC: a low bar, met by the presence of technical means (“any hardware”)
- Intermediate step: identify which features contribute to the technical character of the invention as a whole; exclude those that do not for the purposes of novelty and inventive step
- Novelty and inventive step: assessed using UK methods (e.g. Pozzoli), but only on the eligible feature-set after filtering
This has practical consequences. Under Aerotel, many disputes played out at the exclusion stage by debating “technical contribution”. Under the new approach, far more claims will likely pass the “invention” hurdle and be fought instead on whether the purportedly innovative aspects contribute to technical character at the intermediate step, and whether the remaining technical contribution is novel and non-obvious. That may change both drafting strategy (more focus on articulating technical interaction) and litigation emphasis (more disputes about what is filtered out).
Finally, the Court’s treatment of ANNs carries an important warning: calling an invention “AI” does not avoid the computer program exclusion. The Court was clear that an ANN is a computer program in substance. The question is not whether AI is “software”, but whether the claim’s features (including possibly non-technical ones) interact with technical means (i.e. a hardware) to contribute to the invention’s technical character, and whether the filtered technical contribution is novel and inventive.
In short, Emotional Perception ends Aerotel’s dominance, aligns UK eligibility law with the EPO’s “any hardware” interpretation, and shifts the real patentability battleground to the intermediate step and the conventional novelty/inventive-step analysis that follows.
It is interesting to see here that the highest court in the UK felt itself duty-bound to follow an enlarged board of appeal decision of the EPO. This is particularly so when considering the UK’s position outside of the Unified Patent Court framework: in the wake of Brexit the UPC was prepared to still let the UK participate, but the then prime minister Boris Johnson did not want to have British sovereignty overruled by the European Court of Justice. Here the 20 year British precedent of Aerotel has effectively been overturned by the EPO, which does not even exercise any function as a court.
Lastly, patent offices often take time to react to new case law, and thus it should be expected that the UKIPO may not immediately apply the new decision. What has been seen in the past is that the UKIPO issues new guidelines to Examiners, and already from the UKIPO website there is a disclaimer that the previous AI guidelines have been withdrawn following the decision, so interested parties should stay tuned for more…
