In a significant decision on February 11, with implications for the patentability of artificial intelligence, the Emotional Perception AI Limited v Comptroller General of Patents, Designs and Trade Marks, unanimously allowed an appeal by Emotional Perception AI Ltd. The Court rejected the established four-step approach from the 2006 Aerotel case and aligned the United Kingdom with the jurisprudence of the European Patent Office (EPO). The judgment requires the UK Intellectual Property Office (UKIPO) to adopt a new framework for assessing such inventions and return the application to the UKIPO for reconsideration.

The dispute concerned a patent application for a system that uses an artificial neural network (ANN) to elicit a similar emotional response in a user for recommended media files, such as music or video. The invention’s method involves training an ANN to recognize similarities between files based on their objective physical properties in a way that mirrors subjective human perception. The judgment described the significant “trick” in the invention as training the ANN to adjust how it measures similarity between pairs of files. More specifically, the system aligns the distances between those files in a physical property space with the distances between the same pairs in a semantic space derived from human language descriptions. The UKIPO hearing officer, the High Court, and the Court of Appeal had all previously rejected the application, as it had found that under the Patents Act 1977, it was excluded from patentability as a “program for a computer…as such.” 

Writing for the unanimous Court, Lord Briggs and Lord Leggatt addressed whether UK courts should continue to apply the four-step patent eligibility test from Aerotel Ltd v Telco Holdings Ltd or adopt the approach of the EPO’s Enlarged Board of Appeal, particularly as articulated in its decision G1/19. The Court found compelling reasons to abandon the Aerotel framework, stating that the “strongest reason for rejecting the Aerotel approach is that it has been emphatically rejected as a means of applying article 52(2) and (3) by the Enlarged Board in G1/19.” The judgment criticized the test for improperly mixing the question of whether there is an “invention” with the separate requirements of novelty and inventive step. Instead, the Court endorsed the EPO’s “any hardware” approach, which sets a low bar for the initial determination of whether an invention exists. Under this test, if a claim involves any form of hardware, it is considered an invention and is not immediately excluded from patentability.

The second issue was whether an ANN constitutes a “program for a computer” under article 52(2)(c) of the European Patent Convention (EPC). Emotional Perception AI had argued that its ANN was a physical machine, not a program, and therefore, the exclusion did not apply. The Supreme Court disagreed, concluding that an ANN is indeed a computer program. Additionally, the Court reasoned that an ANN, regardless of whether it is implemented in dedicated hardware or on a conventional computer, is “in essence, a set of instructions to manipulate data in a particular way so as to produce a desired result.” The judgment clarified that an ANN is an “abstract entity or model” and not a physical object itself. The Court held that the entire ANN, including its network topology and mathematical functions, not just its adjustable weights and biases, constitutes the program.

Despite finding that the ANN was a computer program, the Court moved to consider whether the invention was excluded from patentability “as such.” Applying the newly adopted EPO approach, the Court found that the invention was not excluded. Since the claims involved technical means beyond the program itself, such as a communications network, a database, and a user device, the invention possessed the necessary technical character to avoid the exclusion. The judgment stated that this was “sufficient to show that the subject matter of the claims has technical character and is not to a computer program ‘as such.’” This finding directly reversed the lower courts’ decisions, which had all held that the invention, under the Aerotel test, did not make a technical contribution and was therefore excluded.

Having determined that the invention was not excluded from patentability at the initial stage, the Court allowed the appeal and set aside the decision of the UKIPO Hearing Officer. However, the Court declined to conduct the further analysis required under the EPO framework, which involves an “intermediate step” to filter out non-technical features before assessing novelty and inventive steps. The judgment explained that this was a matter for the UKIPO to consider, as the Court had not received sufficient argument on how this new step should be applied in UK law. The case was therefore sent back to the UKIPO to assess whether the invention meets the requirements of novelty and inventive step, taking into account only its technical contributions.

This ruling represents a significant realignment of UK patent law for software and AI-related inventions. By abandoning the Aerotel test, the Supreme Court has aligned the UK more closely with the EPO. While the decision does not guarantee the patentability of all AI inventions, it establishes a new framework for assessing their eligibility. The ruling provides a more permissive initial test, but will now depend on navigating the subsequent hurdles of the intermediate technical-contribution filter, novelty, and inventive step at the UKIPO.