UK Supreme Court reshapes AI patent landscape: abandoning Aerotel for EPO alignment

In a landmark ruling that has sent shockwaves through the intellectual property community, the UK Supreme Court has fundamentally redefined the framework for patenting artificial intelligence (AI) and software-based inventions. Handing down its judgment in Emotional Perception AI Limited (Appellant) v. Comptroller General ( UKSC 3), the Court has formally rejected the long-standing Aerotel test, signaling a decisive move toward harmonization with the European Patent Office (EPO). This “seismic shift” is expected to provide much-needed clarity for innovators while positioning the UK at the forefront of global AI IP jurisprudence.

A decisive departure from tradition

For nearly two decades, the Aerotel/Macrossan four-stage test has governed how the UK Intellectual Property Office (UKIPO) and British courts assessed whether an invention was excluded from patentability as a “program for a computer… as such”. However, the Supreme Court has now instructed that this approach be abandoned in favor of the EPO’s G 1/19 “any hardware” principle.

Alex Burns, IP Director and Patent Attorney at Mewburn Ellis, describes the ruling as a “decisive shift that brings some much-needed clarity and consistency” to the field. By aligning the UK with a “mature, well-understood European framework,” the decision is expected to boost commercial confidence and make the UK a more predictable and attractive jurisdiction for AI investment and patent filing.

Luke Maunder, Partner at Osborne Clarke, notes that the decision will “surprise many” as it overturns such a long-standing precedent. While the shift brings alignment, Maunder warns that it also “introduces a period of uncertainty while the new approach beds in” and the industry awaits further guidance from the UKIPO.

The status of Artificial Neural Networks (ANNs)

At the heart of the appeal was the question of whether artificial neural networks (ANNs) fall under the statutory exclusion for computer programs. The Supreme Court held that ANNs, if implemented in some form of computer hardware, avoid the exclusions from patentability.

The Court confirmed that while ANNs are indeed “programs for computers,” they cannot be excluded purely on that basis if they satisfy the “any hardware” test. Jonathan Ball, Partner at Norton Rose Fulbright, explains that AI and software-based inventions claiming hardware as part of the invention—including the physical form of an ANN or the computer running the software—are no longer considered excluded matter for the initial stages of determining patentability.

This shift has significant implications for AI developers. “The bar for clearing the ‘excluded subject matter’ stage is now ostensibly lower,” Ball notes, which could make it easier for AI companies to secure patent protection in the UK.

A hybrid approach to inventive step

While the Supreme Court moved to align the UK with the EPO on patent eligibility, it stopped short of a wholesale adoption of the EPO’s “problem-solution” approach. Instead, the Court maintained that the UK could continue to use its own Pozzoli approach for assessing inventive step.

However, this comes with a critical caveat: the UK must now adopt the EPO’s “intermediate step” of filtering out features that do not contribute to the technical character of the invention before conducting the Pozzoli analysis. Ben Husband, Partner at Carpmaels & Ransford, clarifies that this means the Court has not signaled a total adoption of EPO practices, but rather a modification of the UK’s existing assessment.

This nuance is significant for practitioners. Katie McConnell, Partner at Hogan Lovells, points out that while the Court brought jurisprudence in line with the EPO regarding patentability, it “left this issue open” regarding a full change to the inventive step approach, deferring such a decision to a case where it may specifically arise.

Strategic implications for the AI industry

The ruling is widely viewed as a “major boost for AI innovators.” Mark Marfé, patent disputes partner at Pinsent Masons, argues that the decision shows the UK courts leading the way in clarifying accountability for AI-based inventions. He notes that, much like the earlier DABUS litigation, this case demonstrates that the most important questions regarding AI and inventorship are being addressed at the highest levels of the UK judiciary.

For designers of AI systems, this level of clarity is vital. “Clarity makes it easier to protect innovation in the UK; something that’s important for attracting investment,” Marfé emphasizes. The decision also provides a practical roadmap for patent attorneys. Carissa Kendall-Windless, IP litigation specialist at Pinsent Masons, suggests that going forward, claim drafting may need to more closely tie machine learning advances to concrete technical effects, such as throughput, cache usage, and numerical stability.

However, some experts suggest that the practical impact on filing strategies may be moderate. Conor McLaughlin, Managing Associate at Mishcon de Reya, notes that because most AI companies adopt a “transnational lens” for their patent strategies, they often focus on European Patent applications that already cover the UK. While the decision makes the UK more predictable, McLaughlin believes it may simply confirm the UK’s alignment with existing European practices rather than sparking a sudden surge in UK-only filings.

The role of the UKIPO as expert examiner

The Supreme Court has referred the Emotional Perception case back to the UK Intellectual Property Office to reassess the application under the revised G 1/19 framework. The Hearing Officer must now decide whether the invention achieves a “further technical effect” and whether the features contributing to its technical character involve an inventive step.

This referral reinforces the role of the UKIPO as an expert venue for resolving complex technical questions. Carissa Kendall-Windless highlights that by reverting the case to the office, the Court has signaled confidence in the UKIPO’s capability as a reliable forum for emerging technologies.

Furthermore, the speed of the legal process has been noted as a strength of the UK system. The entire appellate cycle—from the UKIPO’s original refusal in June 2022 to the Supreme Court judgment in February 2026—took approximately 27 months. Kendall-Windless points out that this is a “rapid trajectory” for such complex technical issues and demonstrates how a common law jurisdiction can adapt dynamically through precedent without waiting for legislative reform.

The Emotional Perception ruling marks the beginning of a new chapter for UK intellectual property law. By abandoning Aerotel and adopting the “any hardware” test, the Supreme Court has removed years of uncertainty and replaced an outdated framework with one that is better equipped for the realities of modern AI development.

While the industry waits for the UKIPO to apply this new test to the facts of the case, the overall sentiment is one of optimism. The judgment not only harmonizes the UK’s approach with the EPO, reducing the risk of inconsistent outcomes, but also strengthens the UK’s position in the global AI IP landscape. As the boundaries between hardware and software continue to blur, the UK has positioned itself as a jurisdiction that is ready to test the limits of AI patent law and provide the legal certainty required by the next generation of innovators.

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