Patents, Artificial Neural Networks and the European Approach

Emotional Perception AI Limited (Appellant) v Comptroller General of Patents, Designs and Trade Marks (Respondent) [2026] UKSC 3 (On appeal from [2024] EWCA Civ 825)

This Supreme Court ruling arose out of an appeal by Emotional Perception AI Limited (“EPAI”) against a 2024 Court of Appeal decision in favour of the Comptroller General of Patents, Designs and Trade Marks (the “Comptroller”). In short, the appeal raised the question of whether it is possible to obtain a UK patent for a system which uses an artificial neural network (“ANN”). An ANN is, simply put, a model that is intended to replicate the function and operation of a human brain. ANNs can be trained to perform tasks and to improve the quality of their performance by a process of comparing their actual outputs with independently generated ‘target’ outputs.

EPAI is a UK-registered company which has developed an ANN-based tool (the “Tool”) for recommending music based on the music’s “emotional similarity” with other music files. The intention behind the development and commercialisation of the Tool is to allow music listeners (and potentially other media consumers) to find new music that provokes a similar emotional response. According to EPAI, this Tool works more quickly and accurately, and provides better music recommendations, than any other product currently on the market. Against this background, EPAI applied to the UK Intellectual Property Office (the “UKIPO”) for a patent for the Tool.

Under UK law (as primarily set out in the Patents Act 1977), which closely replicates the European Patent Convention (the “EPC”), it is not possible to patent “programmes for computers… as such”. On that basis, the UKIPO rejected EPAI’s patent application. The High Court an appeal by EPAI, but the Court of Appeal overturned that High Court decision, reinstating the UKIPO’s original rejection of the application. The matter then came before the Supreme Court, which was required to decide on three separate but related issues:

1. Should the guidance on the application and interpretation of the EPC set out by the Court of Appeal in the case of Aerotel Ltd v Telco Holdings Ltd [2006] EWA Civ 1371, which was relied on by the UKIPO, the High Court and the Court of Appeal, still be followed?
2. Is the Tool (or does the Tool contain) a “programme for a computer”?
3. Is the entire subject matter of the claims (i.e. the Tool) excluded from patentability under the EPC and relevant UK law?

In its judgment handed down on 11^th February 2026, the Supreme Court allowed EPAI’s appeal. In making its decision on each of the three issues listed above, the Supreme Court reasoned as follows:

Issue 1

The Supreme Court first considered the guidance set out in Aerotel, which recommended a four-step approach to the application of the EPC. This four-step approach aimed to determine whether the subject of the patent claim makes a novel technical contribution to the known art. Aerotel had been criticised by the European Patent Office (the “EPO”) in a 2006 decision known as Duns Licensing Associates (Decision T 154/04) [2004] EPOR 10). In that decision, the EPO argued that Aerotel was inconsistent with the EPC and suggested an approach whereby as long as the invention includes a piece of hardware, it cannot be excluded from patentability under the EPC. This position was endorsed by the EPO in G1/19 [2021] EPOR 30.

The Supreme Court, while recognising that UK courts are not bound by EPO decisions, decided in this case that the Aerotel approach should no longer be followed. The Supreme Court held that the approach set out in G1/19 (which itself endorsed the EPO decision in Duns Licensing) was the correct one – i.e. the determination of whether the subject of the patent claim is an invention should come before and separately from the other three conditions of novelty, an inventive step and industrial application. In short, the question of whether the subject of a patent claim is an invention or not is not determined by whether the subject is novel or involves an inventive step.

Issue 2

The Supreme Court decided that to confine the term “computer” in the EPC’s wording “programme for a computer” to conventional digital computers would be out-of-date and anachronistic. In reality, the term “programme for a computer” should be interpreted as a set of instructions capable of being followed by a computer of any kind, to produce desired data outputs. The Supreme Court further endorsed the original IPO decision to characterise ANNs as “abstract model[s] which [take] a numerical input, [apply] a series of mathematical operations (applying weights, biases and an activation function) and [output] a numerical result at successive layers”. An ANN can be implemented in a variety of different types of hardware, meaning that it is not itself a type of hardware. Whatever the form of computer that the ANN is implemented on, it remains a set of instructions capable of being followed by a computer of any kind, to produce desired data outputs. As such, it is a “programme for a computer” within the meaning of the EPC.

Issue 3

Having determined issues 1 and 2 above, the Supreme Court turned to whether the entire subject of the patent (i.e.) the Tool falls within the exclusion of “programmes for computers… as such” and therefore should be excluded from patentability. Applying the approach set out in the G1/19 decision, the Tool is indeed an invention. While it is a programme for computer, it can be implemented on some form of hardware. It therefore clears the first hurdle.

Having done so, the next stage is to determine whether the claim is novel by mirroring the EPO’s so-called “intermediate step” of filtering out features that do not contribute to the technical character of the invention before conducting an analysis into whether the subject of the patent claim qualifies as novel. The Supreme Court, making this decision, then referred the matter back to the UKIPO to decide on the basis of this new approach (i.e. mirroring the EPO’s assessment methodology).

Why this decision matters

This decision is important not so much for its specific subject matter as for the indication it gives as to the UK judiciary’s approach to the application of UK patent law (particularly in the context of artificial intelligence). It was a surprising decision that will require big changes to the UKIPO’s assessment of patent applications and patent lawyers’ approach to applications and disputes. It moves the UK more towards a ‘European model’ and signals that patents in the UK will be more accessible to innovators who wish to avoid exclusions for ANNs, provided that those ANNs are implemented in some form of computer hardware. In summary, this decision opens the door to patenting AI-related inventions and positions the UK as a leading destination for AI innovators in an ever-expanding market.

If you would like any further information or advice on the information mentioned within this article, please contact James Milliken from the Commercial team.

*This information is for guidance purposes only and does not constitute, nor should be regarded as, a substitute for taking legal advice that is tailored to your circumstances.