UK Supreme Court: While hearing an appeal concerning whether an artificial neural network (‘ANN’) constitutes a ‘program for a computer’ for the purposes of the computer program exclusion under Article 52(2)(c) of the European Patent Convention, 1973 (‘EPC’), the Bench of Lord Briggs, Lord Leggatt, Lord Hamblen, Lord Stephens, and Lord Kitchin, held that an ANN does constitute a program for a computer, but that the claimed invention was not excluded from patentability as a computer program ‘as such.’ The appeal was allowed and the matter remitted to the UK Intellectual Property Office (‘UKIPO’) for further assessment of novelty and inventive step.
Background
Emotional Perception AI (‘petitioner’) had applied for a patent for a system and method using an ANN to make media file recommendations such as music tracks, videos, or text, by replicating the subjective emotional similarity a human might perceive between files, using only their objectively measurable physical properties.
According to the petitioner the claimed method works as follows: Pairs of files are independently assessed in two ways: first, by measuring their semantic similarity, which is derived from how humans describe the files in natural language, converted into numerical vectors in ‘semantic space’; and second, by measuring their physical similarity, that is based on properties such as tempo, tone, and volume, expressed as vectors in ‘property space.’ The ANN is then trained, using backpropagation, to align the distances between file pairs in property space as closely as possible to the distances in semantic space. Once trained and its weights frozen, the ANN can recommend files that would elicit a similar emotional response to a given input file, without any further reference to semantic data.
The United Kingdom Intellectual Property Office’s (‘UKIPO’) Hearing Officer had rejected the application on the ground that the claimed invention fell within the exclusion for ‘programs for computers … as such’ under Article 52(2)(c) read with Article 52(3) of the EPC. On appeal, the High Court had allowed the application, holding that an ANN is not a program for a computer at all. The Court of Appeal had reversed that decision and restored the Hearing Officer’s refusal. The applicant then appealed to the Supreme Court.
Analysis, Law and Decision
At the outset, the Court elaborated upon the applicability of the Patents Act, 1977 (‘Act’), which was enacted to implement the EPC. Section 130(7) of the Act provides that its relevant provisions are to have the same effect as the corresponding provisions of the EPC. Article 52 of the EPC provides that patents shall be granted for inventions in all fields of technology, but excludes from patentability, among other things, ‘programs for computers … as such.’
The Court noted that the established UK approach to applying this exclusion was set out in Aerotel Ltd v Telco Holdings Ltd. (2006] EWCA Civ 1371, which required Courts to:
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construe the claim;
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identify the actual contribution;
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ask whether that contribution fell solely within excluded subject matter; and
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check whether the contribution was technical in nature. This approach had been consistently applied in the UK but was never adopted by the European Patent Office (‘EPO’).
Issue 1: Should the Aerotel Approach be Abandoned?
The Court held that the Aerotel approach should no longer be followed. The starting point was the 2021 decision of the EPO Enlarged Board of Appeal in Bentley Systems (UK) Ltd/Pedestrian Simulation, (2021) EPOR 30, which for the first time had authoritatively ruled on the interpretation of Article 52. The Enlarged Board had endorsed the ‘any hardware approach: that a claim involving any hardware is not excluded by Article 52(2), and had adopted the principles set out in the earlier EPO decisions in Comvik GSM AB, (Decision T 641/00)(2004) EPOR 10 and Duns Licensing Associates, (Decision T 154/04)(2004) EPOR 10.
The Enlarged Board in Bentley had implicitly endorsed the criticism in Duns that the Aerotel approach was incompatible with the EPC and not a good-faith implementation of it. Specifically:
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The Aerotel approach wrongly conflated the concept of ‘invention’ under Article 52(1) of the EPC with the separate requirements of novelty and inventive step. It focused on the ‘contribution to human knowledge’ rather than on whether the claim disclosed an invention at all.
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Article 52 must be read as establishing a threshold question: Does the claim amount to an invention? which is logically prior to, and independent of, the questions of novelty and inventive step.
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The Aerotel approach had been expressly rejected by the Enlarged Board as based on a misunderstanding of the EPC.
The Court affirmed that, while UK courts are not strictly bound by EPO decisions, they must follow Enlarged Board rulings unless there is a compelling reason not to. No such reason existed here. Consistency with EPO jurisprudence is a matter of policy and principle, not merely a preference.
The Court also rejected the Comptroller General’s argument that abandoning Aerotel would require wholesale adoption of the EPO’s ‘problem and solution’ method for assessing inventive step. The Court confirmed that the Pozzoli SpA v. BDMO SA, (2007) EWCA Civ 588, approach to inventive step, remains a legitimate method under the EPC. The EPC mandates only that inventive step be assessed against the standard of non-obviousness to the skilled person; it does not prescribe a single method for doing so.
The approach to be adopted in the UK is that set out in the Duns principles (A) through (F), as endorsed in Bentley, together with the ‘any hardware’ test as the primary threshold. Duns principle (G) and the second paragraph of the Comvik headnote, which relate to the EPO’s problem-and-solution methodology, need not be followed as a matter of UK law.
Further, the Court explained that between the ‘any hardware’ threshold and the assessment of inventive step, an ‘intermediate step’ is required. This involves identifying which features of a mixed (technical and non-technical) invention contribute to its technical character, and filtering out those that do not, before proceeding to assess novelty and inventive step. This intermediate step is implied by Article 52 of the EPC itself and is a necessary part of applying the EPC correctly.
Issue 2: Is an ANN a ‘Program for a Computer’?
The Court held that an ANN is a program for a computer, agreeing with the Court of Appeal’s conclusion but differing in some of its reasoning.
The applicant had argued that a ‘hardware ANN’, which is a physical machine embodying a neural network, is not a computer at all, and that even a ‘software ANN’ running on a conventional computer contains no program, because the weights and biases are generated by training rather than written by a human programmer.
The Court rejected both limbs of this argument.
First, the Court agreed with the applicant and the interveners that the Court of Appeal’s definition of a computer as simply ‘a machine which processes information’ was too broad as it would encompass devices such as a basic oven or an analogue radio. However, the Court also rejected the applicant’s attempt to confine ‘computer’ to conventional digital computers with a central processing unit (‘CPU’). The Curt observed that the EPC must be interpreted in a technology-neutral manner capable of accommodating future developments, including analogue computers, quantum computers, and dedicated hardware of other kinds.
Second, the Court held that the distinction between a ‘hardware ANN’ and a ‘software ANN’ is legally untenable. An ANN is not a physical machine but an abstract model: a series of mathematical operations performed on data as it passes through layers of artificial neurons, each applying weights, biases, and an activation function. An ANN can be implemented on conventional computers, neuromorphic hardware, or field-programmable gate arrays. The choice of hardware is a practical one and does not affect the nature of the ANN itself.
The Court held that, whatever the form of implementation, an ANN constitutes a set of instructions to manipulate data in a particular way to produce a desired result. It is therefore a program for a computer. The relevant ‘instructions’ include not only the weights and biases but also the network’s topology, the number of layers and neurons, and the activation functions, all of which, taken together, determine how the machine processes data. The Court further held that it is irrelevant that the weights and biases are generated through machine learning rather than written directly by a human, and irrelevant that they cannot be predicted in advance.
Issue 3: Is the Claimed Invention Excluded as a Computer Program ‘As Such’?
Applying the ‘any hardware’ approach endorsed in Bently, the Court held that the claimed invention is not excluded from patentability as a computer program ‘as such.’ The claims involve not only an ANN but also a database, a communications network, and a user device, all of which require or constitute hardware. The involvement of this technical hardware is sufficient to demonstrate that the subject matter has technical character and is not a program for a computer ‘as such’ within the meaning of Article 52(2)(c) read with Article 52(3).
The Court therefore held that the UKIPO was wrong to refuse the application on the ground that it fell within the computer program exclusion.
The Court declined to proceed further and carry out the ‘intermediate step’ itself, or to assess novelty and inventive step. The Court did not wish to create binding precedent on these important questions without the benefit of detailed legal argument and the views of the specialist courts and the UKIPO. The matter was accordingly remitted to the Hearing Officer for fresh consideration.
[Emotional Perception AI Ltd. v. Comptroller General of Patents, Design and Trade Marks, (2025) UKSC 3, decided on 11-2-2026]
Advocates who appeared in this case :
For the Appellant: Kings Counsel Mark Chacksfield, Edmund Eustace
For the Respondent: Brian Nicholson, Anna Edwards-Stuart, Kings Counsels