Adjusting the hurdles: UK Supreme Court backs European test for software inventions

The ruling simplifies the assessment of patent eligibility in the UK and may enhance the UK’s reputation as a patentee‑friendly jurisdiction for AI and software inventions. These and related issues are explored in this article.

Background

The ruling concerns the patentability of artificial neural networks, ANNs, but has broader application to the patentability of other types of so-called “mixed” inventions that combine technical (e.g., hardware) and non-technical (e.g., mathematical method as such) features.

Emotional Perception’s patent application –the relevant claims are directed to an ANN-based system and corresponding method for providing file recommendations – enables a file recommendation service that, according to Emotional Perception, makes better file recommendations and is simpler and quicker than anything else currently available. The patent application was refused by the UK Intellectual Property Office, UK IPO², as being excluded from patentability as “a program for a computer… as such” of the Patents Act 1977. That refusal was overturned following Emotional Perception’s appeal to the High Court³, but was later reinstated following the UK IPO’s appeal to the Court of Appeal⁴. The matter was ultimately brought before the Supreme Court following a further appeal by Emotional Perception.

In general terms, the method involves training an ANN to replicate emotional or subjective human perception of the degree of similarity or difference between files of the same genre (music or text, for example) by reference to objectively measurable physical properties of the same files. As noted by the Court of Appeal, the “trick” of the invention is that the ANN is trained to make the distances between pairs of files in a property space, which reflects physical properties such as tempo and tone, align more closely with the distances between those pairs in a semantic space. The Supreme Court described the semantic space as –

“Using music files as an example, at a very basic level one file in a pair might be described as happy and exciting and the other as sad and relaxing, although the descriptions are usually more complex than that. Using a natural language processing system, the textual descriptions are given numerical expression as vectors in what is described as the semantic space.” (paragraph [9])

The claimed invention involves providing the ANN alongside a database, a communications network and a user device, i.e., types of hardware. Historically, such inventions can be difficult to patent as they present challenges for practitioners, patent office examiners, and the courts when assessing whether the contribution (i.e., the clever part or “trick”) of the invention is eligible for patent protection or falls within an area that is excluded from patent protection. As reflected in the history of the proceedings here, borderline cases are particularly challenging, with the Supreme Court having to decide whether to set down new law as to determining the patentability of ANNs and other types of “mixed” invention.

The previous test

Prior to the Supreme Court’s ruling, the test for patent eligibility in UK patent law was laid out in Aerotel Ltd v Telco Holdings Ltd⁵:

• properly construe the claim;
• identify the actual contribution;
• ask whether it falls solely within the excluded subject matter;
• check whether the actual or alleged contribution is actually technical in nature.

Despite the test having been settled case law for nearly 20 years, its application has caused difficulty for software patent practitioners in the UK, with even the lower courts to the Supreme Court’s ruling reaching conflicting conclusions on patent eligibility, as summarised above.

A further practical challenge has been the UK IPO’s refusal to search the claims of a UK patent application directed to a software or AI invention if they believe the Aerotel test leads to a finding of an excluded contribution that cannot be overcome⁶,⁷. The applicant is then at a disadvantage in respect of deciding whether to continue UK prosecution (or, if the UK patent application is a priority filing, deciding whether to seek patent protection abroad), since no search report is issued that otherwise provides an indication of whether the claims appear to be novel and inventive.

The Supreme Court's ruling

Aerotel should no longer be followed

A first outcome of the ruling is the Supreme Court’s agreement with the European Patent Office’s (EPO’s) approach to assessing patent eligibility, finally approved in decision G/19 by the Enlarged Board of Appeal, that –

[The approach] construes that term [“invention”] in light of the basic requirement that patents are to be extended only to that which is technical, as enshrined generally in article 52(1) and treating article 52(2) as providing anon-exhaustive list of examples of matters which are non-technical.” (paragraph [60])

This test, described at paragraph [60] as “uncluttered with any assessment of contribution, novelty or inventive step,” imposes a lower hurdle to patent eligibility than Aerotel because it applies a single criterion: does a claim involve “any hardware”. Since Emotional Perception’s claimed invention includes types of hardware, it passes the “any hardware” test and is therefore not excluded from patent protection under the Supreme Court’s ruling.

This test, described at paragraph [60] as “uncluttered with any assessment of contribution, novelty or inventive step,” imposes a lower hurdle to patent eligibility than Aerotel because it applies a single criterion: does a claim involve “any hardware”. Since Emotional Perception’s claimed invention includes types of hardware, it passes the “any hardware” test and is therefore not excluded from patent protection under the Supreme Court’s ruling.

 An ANN is a computer program

A second outcome of the ruling is that –

“Whatever the specific form of the machine on which an ANN is implemented, the ANN constitutes, in essence, a set of instructions to manipulate data in a particular way so as to produce a desired result.” (paragraph [87])

It is irrelevant, in the Supreme Court’s view, whether the weights and biases of an ANN are baked into hardware and cannot be changed, or can be altered on hardware that is either “hard-wired” or which can be reconfigured (paragraph [91]). Whether the weights and biases can be adjusted through training or are unknown in advance is also irrelevant (paragraphs [93] and [94]).  What matters is that the ANN is an abstract entity or model and not a physical object (paragraphs [81] and [84]). It is therefore not a computer (which is a physical object), with the Supreme Court commenting, at paragraph [84], that “the Court of Appeal was in our view mistaken in describing it as such.”

Accordingly, a “computer” in UK patent law should not be tied to a computing technology that happens to be currently prevalent. This implies that instructions in the sense of paragraph [87] (reproduced above) for new computing technologies, even if based on physical principles that differ fundamentally from those of conventional computing (such as quantum computing), are also abstract entities. They will therefore likewise fall within the scope of the term “program for a computer”.

Assessing the patentability of a “mixed” invention in the UK will now involve applying an “intermediate step”

The Supreme Court also agreed with the EPO’s “Comvik approach”⁸ and “Duns principles”⁹, endorsed by G1/19, of including a determination between “any hardware” and inventive step as to which features in a “mixed” invention contribute to its technical character (and may therefore be patentable).  

The determination is more than a mere filtering out of non-technical features as such, as non-technical features may interact with the technical subject matter of a claim to contribute to the technical character of the claimed invention (one of the seven “Duns principles”). Similarly, technical features are filtered out if they “cannot contribute to inventive activity because they have no technical function within the context of the claimed invention”¹⁰.

The Supreme Court did not accept arguments advanced on behalf of the Comptroller General that the intermediate step would introduce an incompatibility or “create a Frankenstein monster” with respect to the long-settled Pozzoli test¹¹ used in the UK to assess inventive step -

 “But, in short, we do not regard Comvik, Duns and G1/19 as deciding or suggesting that the problem and solution approach of the EPO is the only way of assessing inventive step, or the only way of factoring the exclusions in article 52(2) into the overall appraisal of patentability.” (paragraph [54])

Summary of the Supreme Court’s ruling

The Supreme Court allowed Emotional Perception’s appeal and set aside the Hearing Officer’s refusal. The claimed invention and the question of how to apply the “intermediate step” will now be referred back to the UK IPO for further consideration.

As the claimed subject matter has been found not to be excluded from patentability by being directed to “a program for a computer… as such”, the “intermediate step” will be required to assess whether certain features of the claim should be ignored for the purpose of assessing inventive step because they do not contribute towards the technical character of the claim.

The Supreme Court declined to further consider the “intermediate step” to avoid creating a legal precedent without the benefit of the expert views of both the UK IPO and specialist judges in the lower courts. Instead, it referred the issue back to the UK IPO, for argument on the subject to be heard in full. The exact application of the “intermediate step” in the UK therefore remains unsettled for now.

“Essentially for good policy reasons”: Harmonisation with settled European software patent law benefits UK patent applicants

At the time of writing, the UK IPO has withdrawn its Guidelines for examining patent applications relating to artificial intelligence following the Supreme Court’s ruling. It is not possible, as things currently stand, to say whether the claimed invention at issue provides a technical contribution under the new UK patent law.

That said, the Supreme Court’s ruling is clearly good news for more harmonisation between UK and European patent law. It imports from the EPO a simpler test for patent eligibility – streamlining this aspect of patent prosecution in the process – and overturns a problematic definition of the term “computer” as encompassing an abstract entity. The ruling also endorses most of the EPO’s approach to assessing “mixed” inventions, which UK practitioners are already familiar with –

“We have concluded that this was the wrong approach, and that the approach set out by the Enlarged Board in G1/19 should be applied, adopting all but the last of the Duns principles.” (paragraph [113])

Here, the last of the “Duns principles” concerns a different test for the assessment of inventive step – namely the EPO’s preferred problem-solution approach – than the Pozzoli test used in the UK.

While the “intermediate step” and its interaction with Pozzoli may themselves become the subject of a future appeal, we encourage the UK IPO to issue updated guidance in the near future to provide certainty to applicants on the examination of “mixed” inventions. In our view, this update should also address search practices and clarify under what, if any, circumstances the UK IPO would extend ex officio the compliance period for pending applications that are currently subject to an Aerotel objection.  

Whether or not the UK becomes more friendly than the EPO on patenting software and AI inventions remains to be seen. In our view, a significant divergence appears unlikely given the Supreme Court’s position that decisions of the Enlarged Board of Appeal and unform jurisprudence of the Boards of Appeal should be respected and followed “unless convinced that they are wrong or beyond the ambit of reasonable difference of opinion.” (paragraph [44]).

Regardless of whether patent protection in the UK is sought through the UK IPO or the EPO, the strength of a patent application for a software or AI invention will continue to depend on its substance: whether the claimed invention provides a credible, non-obvious technical solution to a technical problem. Lowering the eligibility hurdle does not necessarily make the rest of the patentability race easier.

References

1. https://www.supremecourt.uk/cases/judgments/uksc-2024-0131
2. Patent decision BL O/542/22
3. Emotional Perception AI Ltd v Comptroller-General of Patents, Designs and Trade Marks [2023] EWHC 2948 (Ch) (21 November 2023)
4. Comptroller General of Patents, Designs and Trade Marks v Emotional Perception AI Ltd[2024] EWCA Civ 825 (19 July 2024)
5. Aerotel Ltd. v Telco Holdings Ltd & Ors Rev 1 [2006] EWCA Civ 1371 (27 October 2006)
6. Section 17(5)(b) Patents Act 1977
7. Manual of Patent Practice, 17.94
8. T 0641/00
9. T 0154/04
10. G1/19, paragraph 33
11. Pozzoli Spa v BDMO SA & Anor [2007] EWCA Civ 588 (22 June 2007)