Navigating the Post-Aerotel Landscape: The UKIPO’s "Two-Implementation" Approach to Mixed-Type Inventions

As practitioners will recall, the Supreme Court fundamentally altered the assessment of excluded subject matter in the UK. The Court axed steps 2 to 4 of the long-standing Aerotel test, mandating instead that an "intermediate step" be used to filter out features that do not contribute to the technical character of the claim when assessing mixed-type inventions. While the Court ruled that an Artificial Neural Network (ANN) does constitute a computer program, it found that Emotional Perception’s invention possessed technical character and was not a computer program "as such," thereby clearing the first patentability hurdle.

However, the Supreme Court declined to provide strict guidance on exactly how examiners should implement this new intermediate filtering step during the second hurdle: the assessment of inventive step.

A newly issued Examination Report on the remitted Emotional Perception application (GB1904713.3), dated 27 March 2026, reveals how the UKIPO is navigating this transitional period. To ensure robustness, the examiner applied two parallel "implementations" of the Supreme Court's intermediate step. It is highly probable that this dual-track examination is merely a temporary safeguard. As Office practice settles and new precedent is established, we expect that the UKIPO will eventually drop the belt-and-braces approach, and one of these implementations will emerge to dominate standard practice.

Implementation 1: Filtering Before Prior Art Comparison

In the first implementation, the examiner applies the intermediate step to filter the claim before making any comparison to the prior art.

The examiner evaluates the invention as a whole to determine which features contribute to its technical character. In this specific case, the examiner determined that several core characteristics lacked technical character:

• The formulation of semantically relevant recommendations.
• The use and internal workings of the ANN.
• The underlying mechanism for training the ANN.

Because these features did not relate to a technical solution for a technical problem, the examiner stripped them out. After filtering, the only remaining features were generic computer hardware elements: a processor capable of hosting models, memory, a communications network, and a user device. When this filtered, generic system was compared to the cited prior art (an Apple patent application), the examiner concluded that any differences were purely non-technical, resulting in a lack of inventive step.

Implementation 2: Filtering After Identifying Differences (The Comvik Approach)

In the second implementation, the examiner applies the filter after identifying the differences over the prior art, heavily mirroring the EPO's well-known Comvik approach.

• The examiner first utilizes the traditional Pozzoli framework to identify the inventive concept and the differences between the claim and the closest prior art.
• The examiner then applies the intermediate filtering step specifically to those differences.
• Because the differences in this application (the ANN, its training methods, and the semantic similarity identification) were deemed devoid of technical character, they were filtered out.
• Consequently, the claim was found to lack the required inventive step.

Takeaways for Applicants

While still not actually taking a position on how, precisely, such cases should be handled, the UKIPO has made its position clear on this particular application: both implementations currently arrive at the exact same destination. While the Supreme Court's ruling may have made it easier for AI and software inventions to survive the initial Section 1(2) exclusion hurdle, the battleground has shifted to the assessment of inventive step.

Going forward, it is not enough for an AI system to simply possess an overarching "technical character." Patent applicants must meticulously draft their claims and specifications to demonstrate how the distinguishing features provide (possibly via interaction with other elements) technical character. Without this, applications will falter at the newly fortified inventive step hurdle.

What’s Next: A Return to the Courts?

Given the high-profile nature of the Emotional Perception case, and the fact that the examiner could not identify any amendable features in the specification to overcome these rejections, this application is almost certainly heading to a UKIPO Hearing Officer.

However, the journey is unlikely to end there. Because this case represents the very tip of the spear for interpreting the Supreme Court’s new framework, this application may be appealed back through the courts and the judiciary may soon be forced to weigh in once again, this time to explicitly mandate exactly what is the legally correct manner for the UKIPO to apply the intermediate filtering step (i.e. to require that technical character is present). Until then, practitioners should prepare their AI applications to withstand a range of possible approaches.

If you have any questions on this subject, or would like assistance with protecting your invention, please contact your usual D Young & Co representative.