UKSC Aligns Patent-Eligibility for Computer-Implemented Inventions with EPO G1/19: Aerotel Replaced; ANNs Treated as Computer Programs; “Any Hardware” Restored
1. Introduction
This appeal addressed whether inventions centred on artificial neural networks (“ANNs”) can be patented under the UK framework implementing the European Patent Convention (“EPC”), and in particular how the exclusion for “programs for computers … as such” in EPC article 52(2)(c) and (3) should be applied.
The appellant, Emotional Perception AI Limited, sought a patent for a recommendation method/system that trains an ANN to align distances between files in a “property space” (derived from objectively measurable physical properties of files such as tempo, tone, rhythm) with distances in a “semantic embedding space” (derived from natural-language descriptions of human-perceived characteristics). After training, the ANN generates vectors for new files based only on measurable properties, enabling “emotionally similar” recommendations without using semantic descriptions at inference time.
The respondent, the Comptroller General of Patents, Designs and Trade Marks, resisted the grant on the basis that the claims were excluded as a “program for a computer … as such”. The case also became a vehicle for resolving a major methodological conflict between longstanding UK authority (Aerotel Ltd v Telco Holdings Ltd [2006] EWCA Civ 1371; [2007] Bus LR 634; [2007] RPC 7 (“Aerotel”)) and the EPO Enlarged Board’s decision in Bentley Systems (UK) Ltd/Pedestrian Simulation (Decision G1/19) [2021] EPOR 30 (“G1/19”).
Key issues
- Issue 1: Should the UK stop applying the Aerotel four-step approach, and instead adopt the interpretation of EPC article 52 in G1/19?
- Issue 2: Is an ANN a “program for a computer” within article 52(2)(c)?
- Issue 3: If so, are these claims excluded as a program “as such”, or do they nevertheless have technical character and proceed to novelty/inventive step?
2. Summary of the Judgment
The Supreme Court (Lord Briggs and Lord Leggatt, with Lord Hamblen, Lord Stephens and Lord Kitchin agreeing) allowed the appeal.
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Aerotel should no longer be followed. The UK must adopt the EPO Enlarged Board’s interpretation of EPC article 52 as articulated in G1/19, including the “any hardware” understanding of what clears the eligibility hurdle of article 52.
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ANNs are “programs for computers”. The Court rejected the notion that ANN-based inventions avoid the computer program exclusion because an ANN is not a program; rather, an ANN is an abstract model that constitutes instructions for a computer (broadly understood) to manipulate data.
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But these claims are not excluded as a program “as such”. Under the “any hardware” approach endorsed in G1/19, the presence of technical means (computer hardware, database, network, user device) gives the claimed subject matter technical character, so it is not excluded at the eligibility stage.
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Next steps remitted to UKIPO. The case was sent back for consideration of novelty and inventive step, including application of the intermediate “filtering” step described in G1/19 (to determine which features contribute to technical character and may count for inventive step), without the Supreme Court attempting to apply that step to the claims on the existing record.
3. Analysis
3.1 Precedents Cited (and their Influence)
(a) The UK line culminating in Aerotel
The Court traced how Aerotel developed a four-step test that (i) construes the claim, (ii) identifies the “actual contribution”, (iii) asks whether it falls solely within excluded subject matter, and (iv) checks whether the contribution is “technical in nature”. This approach drew on earlier UK authorities such as Merrill Lynch's Application [1989] RPC 561, Gale's Application [1991] RPC 305, and Fujitsu Ltd's Application [1997] RPC 608.
However, the Supreme Court held that Aerotel effectively collapses eligibility (article 52) into novelty/inventive step by focusing on what the inventor “has really added to human knowledge”. That, the Court held, conflicts with the EPC structure in which “invention” is a threshold question distinct from novelty and inventive step.
(b) The EPO’s approach: Comvik GSM AB (Decision T 641/00) [2004] EPOR 10 and Duns Licensing Associates (Decision T 154/04) [2004] EPOR 10
Comvik addressed inventive step for “mixed” claims containing technical and non-technical features, holding that inventive step can rest only on features contributing to technical character. Duns criticised approaches (including the UK’s) that mix the “invention” inquiry with prior art considerations, stressing the separateness of EPC article 52(1)’s four requirements and the need to test “invention” before novelty and inventive step. The Supreme Court treated these cases as foundational to understanding G1/19.
(c) The turning point: Bentley Systems (UK) Ltd/Pedestrian Simulation (Decision G1/19) [2021] EPOR 30
G1/19 endorsed the “any hardware” threshold and approved the “Duns principles”. It also framed a “two-hurdle approach” (eligibility under article 52, then inventive step under article 56) as effectively involving a further intermediate step: determining which claim features contribute to technical character and are therefore eligible to contribute to inventive step.
The Supreme Court held that G1/19 represents authoritative EPO interpretation of the EPC which UK courts should follow for reasons of uniformity, unless convinced it is wrong beyond reasonable disagreement—which they were not.
(d) Uniformity and “dialogue” with the EPO
The Court relied on the established UK principle that, while EPO decisions are not binding, UK courts should generally follow consistent EPO jurisprudence:
These authorities were used to justify revisiting entrenched domestic methodology once the Enlarged Board had spoken.
(e) Inventive step methodology remains (for now) UK-native
The Comptroller argued that adopting G1/19 would require adopting the EPO “problem and solution” method and displacing the UK’s Pozzoli SpA v BDMO SA [2007] EWCA Civ 588; [2007] FSR 37 approach (approved in Actavis Group PTC EHF v ICOS Corpn [2019] UKSC 15; [2019] Bus LR 1318; [2019] RPC 9). The Supreme Court rejected that as a necessary consequence: EPC article 56 requires only that the inventive step be “not obvious”, leaving room for different legitimate domestic methodologies, provided the EPC’s interpretive commitments are honoured (including filtering out non-technical features).
(f) Hardware implementation vs software implementation: Vicom/Computer-related invention (Decision T 208/84) [1987] 2 EPOR 74
Vicom was cited for the proposition that it is inappropriate to distinguish between hardware and software embodiments of the same invention. The Supreme Court applied this logic to reject the appellant’s attempt to privilege “hardware ANN” as “real” and treat software implementations as mere emulations.
(g) EPO cases on “any hardware” and computer-implemented claims
PBS Partnership/Controlling pension benefits system (Decision T 931/95) [2002] EPOR 522 (“Pension Benefits”), Hitachi/Auction method (Decision T 258/03) [2004] EPOR 548 (“Hitachi ”), and Microsoft/Clipboard formats I (Decision T 424/03) [2006] EPOR 414 (“Microsoft/Data Transfer”) appeared in Aerotel as variants of “any hardware”, which Aerotel had criticised. Their relevance in the Supreme Court’s reasoning was mainly historical: they illustrated the divergence that G1/19 resolved.
(h) ANN-as-program reasoning supported by EPO: Mitsubishi/Sparsely connected neural network (Decision T 702/20) 7 November 2022
The Supreme Court agreed with Mitsubishi/Sparsely connected neural network (Decision T 702/20) 7 November 2022 that the unpredictability of trained parameters to humans does not prevent an ANN from operating according to its programmed structure and training scheme; given the training data and procedure, outputs are determined by that “programming”.
3.2 Legal Reasoning
(A) Why Aerotel was rejected
The Court’s reasoning is fundamentally structural and treaty-based: EPC article 52(1) sets four distinct requirements (invention, novelty, inventive step, industrial application). Article 52(2) and (3) address what counts as an “invention” and the scope of exclusions “as such”. The Supreme Court held that Aerotel is misaligned with that structure because it begins by asking about “contribution” to the “known art” (inviting prior art and inventiveness considerations), which the EPC allocates to articles 54–56.
The Court accepted the EPO critique (originating in Duns Licensing Associates (Decision T 154/04) [2004] EPOR 10 and endorsed in G1/19) that using “invention” in the lay sense of a novel contribution, rather than as the EPC’s threshold category, is a “legal fallacy”.
(B) The UK replacement framework: “any hardware” + intermediate filtering
The Supreme Court held that UK decision-makers should apply the G1/19/Duns interpretation of article 52, including:
- Eligibility (“invention”) stage: a computer-implemented method involving technical means is an “invention”.
- Intermediate step: identify, feature-by-feature, which aspects contribute to the technical character of the invention as a whole; only those can support novelty/inventive step.
- Inventive step stage: assess obviousness using a legitimate method (the Court did not mandate the EPO’s “problem and solution” method, and did not displace Pozzoli SpA v BDMO SA [2007] EWCA Civ 588; [2007] FSR 37).
Crucially, the intermediate step is not the old Aerotel “is the contribution technical?” holistic check; it is a filtering exercise concerned with what features are allowed to count in the inventive step inquiry.
(C) ANNs as “programs for computers”
On issue 2, the Supreme Court held:
- The Court of Appeal’s definition of a computer as merely “a machine which processes information” was too broad, but the appellant’s attempt to restrict “computer” to a CPU-based digital computer was also rejected as technologically parochial.
- An ANN is best understood as an abstract model (a set of mathematical operations and network topology) that can be implemented on varied hardware (conventional CPU, dedicated hardware, FPGA, neuromorphic systems). This shows an ANN is not identical to any one physical “box”.
- Nevertheless, an ANN constitutes a set of instructions to a computer to manipulate data—via topology, activation functions, weights and biases—so it is a “program for a computer” within article 52(2)(c).
- It is irrelevant that parameters are learned rather than hand-coded; programs can generate programs, and the legal concept does not turn on whether a human can foresee the trained values.
(D) Why these claims are not “as such” excluded
Applying “any hardware”, the claims included technical means beyond the abstract algorithmic model: they required computer hardware to run the ANN and referred expressly to a database, communications network, and a user device. Therefore, while the computer program exclusion is “engaged” (because an ANN is a computer program), the claims are not excluded at the article 52 stage as a program “as such”.
The Supreme Court therefore set aside the refusal and remitted the application to the UKIPO for novelty and inventive step assessment with the G1/19 intermediate filtering step in mind.
3.3 Impact
(1) Immediate doctrinal impact: end of Aerotel as the eligibility framework
The most significant effect is institutional: UKIPO examiners and UK courts must stop applying the Aerotel steps 2–4 as the governing approach to EPC/Patents Act section 1(2) exclusions and instead align with the G1/19 interpretation. This is a major reorientation of UK “computer program” exclusion analysis.
(2) Practical impact: more applications reach novelty/inventive step, but face tighter filtering
Because “any hardware” sets a low eligibility bar, more computer-implemented inventions (including AI/ML claims) should pass the article 52 threshold and be examined on novelty and inventive step. However, G1/19’s intermediate step means that many “non-technical” features will be filtered out and cannot support inventiveness. This is likely to shift contestation from “is it excluded?” to “what technical features remain and are they non-obvious?”
(3) AI patent strategy: ANNs will not “escape” as non-programs
The Court’s express conclusion that ANNs are “programs for computers” closes a line of argument that ANN inventions avoid the computer program exclusion by categorisation. Future AI patentability battles will likely focus on:
- identifying the invention’s technical character “as a whole”;
- demonstrating interaction between non-technical and technical features such that the former “contribute” and are not filtered out;
- showing the remaining technical features support novelty and inventive step.
(4) Harmonisation with Europe
By aligning UK interpretation with EPO Enlarged Board authority, the judgment reduces divergence risk for applicants prosecuting parallel UK/EPO portfolios and supports predictability in cross-border patent strategy.
4. Complex Concepts Simplified
“Programs for computers … as such”
EPC article 52 excludes “programs for computers” only “as such”. This means not every invention involving software is excluded. Under the endorsed EPO approach, if the claim involves technical means (hardware), it generally has technical character and is not excluded at the eligibility stage—though that does not guarantee patentability.
“Any hardware” approach
A computer-implemented method avoids exclusion under article 52 merely by being tied to technical means (a computer, storage medium, networked device, etc). The “hard work” then occurs later, at inventive step, after filtering out features that do not contribute to technical character.
“Mixed” inventions and the intermediate filtering step
Many claims combine technical elements (computers, sensors, networks) with non-technical aims or rules (business logic, aesthetic content, human-language categories). G1/19 requires identifying which features actually contribute to the technical character of the invention as a whole. Features that do not contribute are ignored when deciding whether the invention is new and non-obvious.
ANNs as “abstract models” yet still “programs”
The Court accepted that an ANN is not a physical machine; it is an abstract model (topology + mathematical functions + parameters). But when that model is implemented on hardware, it functions as instructions that make the computer manipulate data in a specific way—hence a “program for a computer”.
5. Conclusion
Emotional Perception AI Ltd v Comptroller General of Patents, Designs and Trade Marks resets UK patent-eligibility analysis for computer-implemented inventions. It (i) decisively displaces the Aerotel framework in favour of the EPO Enlarged Board’s interpretation in Bentley Systems (UK) Ltd/Pedestrian Simulation (Decision G1/19) [2021] EPOR 30, (ii) establishes that ANNs are “programs for computers” for the purpose of EPC article 52(2)(c), and (iii) confirms that claims involving technical means will ordinarily clear the article 52 “invention” hurdle, leaving patentability to be determined principally through novelty and inventive step—after applying the crucial intermediate filtering step to isolate features that truly contribute to technical character.