The UK Supreme Court’s decision of 11 February 2026 on Emotional Perception AI Limited (Appellant) v Comptroller General of Patents, Designs and Trade Marks (Respondent) ([2026] UKSC 3) marks a major shift in the law of computer‑implemented inventions. The Court has formally abandoned the Aerotel ([2006] EWCA Civ 1371) approach, bringing the UK’s excluded subject‑matter analysis closer to the EPO’s approach. The judgment emphasises alignment with the EPC, noting that the Enlarged Board of Appeal “needs to be respected unless convinced that they are wrong beyond the ambit of a reasonable difference of opinion”.
At the same time, the Supreme Court was not willing to fully rip up UK doctrine and start again. It deliberately avoided importing the EPO’s full problem–solution approach, choosing instead to maintain the UK’s established tests for novelty and inventive step, the Pozzoli test ([2007] EWCA Civ 588). The result is a hybrid system: EPO approach at the “is it an invention?” stage, but still distinctly UK at the inventive‑step stage.
Why is the UK “uninstalling” Aerotel?
The reason for abandoning the Aerotel approach is that it has received significant criticism, and the Enlarged Board in G1/19 has implied that it is incompatible with the EPC. At the core of the judgment is the finding that Aerotel misunderstood what “invention” means under Article 52, because its four‑step test “at best jumbles up the test of an invention with the other requirements for patentability” (paragraph [63]). Instead of assessing whether the claimed subject‑matter is an invention as a standalone question, Aerotel collapsed this threshold inquiry into later patentability criteria. The Aerotel approach was also “emphatically rejected” by the Enlarged Board in G1/19 and described as not being “a good faith implementation of Article 52” of the EPC (paragraph [18]).
Aerotel was decided at a time when the approach to Article 52 had not yet been settled (paragraph [17]). By G1/19, however, the interpretation of Article 52 had become much more settled, and the Supreme Court makes clear that the Enlarged Board of Appeal needs to be respected unless convinced that they are wrong beyond the ambit of a reasonable difference of opinion. It is therefore appropriate for the UK to update its approach to analysing what constitutes an ‘invention’ and to align more closely with the Enlarged Board’s interpretation.
The Court also found Aerotel’s “actual contribution” test fundamentally flawed because it asked what the inventor had “really added to human knowledge” (paragraph [59]). This approach imports novelty and inventive step considerations into the exclusion analysis, even though novelty belongs under Article 54 and inventive step under Article 56, not Article 52. This approach fails to address the true Article 52 question of whether the subject‑matter of the claim is an invention (paragraph [59]). As the Court explains at paragraph [63]:
Aerotel “goes straight to identifying the actual contribution made by the claim, and then asks whether the contribution, rather than the invention, falls solely within the subject matter excluded by article 52(2)”.
What is the “upgrade”?
The UKSC stated that the approach which should be adopted is contained in the Duns principles explained in the reasoning of the Enlarged Board of Appeal at the EPO. Duns Licensing (T0154/04) is an EPO Board of Appeal case which followed another EPO Board of Appeal case COMVIK (T0641/00). As an aside, COMVIK provides an approach for assessing inventive step with a claim that includes both technical and non-technical features (so called, “mixed” claims).
Returning to the Duns principles, principles (A) to (D) essentially explain the four requirements of patentability: there must be an ‘invention’, the ‘invention’ must be novel, inventive, and industrially applicable, which are each distinct hurdles. By adopting these principles, the Court aligns the UK with the EPO’s “any hardware” approach, under which the presence of any technical means is enough to pass the first “invention” hurdle.
Duns principles (E) and (F) then explain that an “intermediate step” has to be undertaken before determining if inventions with non-technical features possess an inventive step; these are reproduced below:
(E) For examining patentability of an invention in respect of a claim, the claim must be construed to determine the technical features of the invention, i.e. the features which contribute to the technical character of the invention.
(F) It is legitimate to have a mix of technical and ‘non-technical’ features appearing in a claim, in which the non-technical features may even form a dominating part of the claimed subject matter. Novelty and inventive step, however, can be based only on technical features, which thus have to be clearly defined in the claim. Non-technical features, to the extent that they do not interact with the technical subject matter of the claim for solving a technical problem, i.e. non-technical features ‘as such’ do not provide a technical contribution to the prior art and are thus ignored in assessing novelty and inventive step.
The UKSC expressed this point succinctly, at paragraph [66] of their judgment:
“66. In our view, the approach which should be adopted by courts in the UK is that contained in the Duns principles other than principle G (and the second paragraph of the Comvik headnote) …. This is for the purpose of excluding non-technical features (ie features which do not contribute to the technical character of the invention) when assessing at the next stage whether the invention involves an inventive step in relation to the prior art.”.
Although, the Duns principles are considered in G1/19 in the context of the EPO’s problem–solution approach, the UKSC makes clear that in UK practice “the approach to inventive step laid out in Pozzoli remains a legitimate approach”. This resonates with us because even at the EPO, the problem-solution approach is not the only way to assess inventive step. As the UKSC states at paragraph [33]: “This method [i.e., problem-solution approach] is not described as the only legitimate test, or one dictated by the true interpretation of the EPC”.
Therefore, this ‘upgrade’ provided by the UKSC can be summarised as: i) “any hardware” (relating to Duns principles (A) to (D)); ii) the intermediate step (relating to Duns principles (E) and (F)); and iii) the UK’s existing Pozzoli approach to inventive step.
Do compatibility issues await?
One issue we have considered is whether this leads to a workable approach to assessing patentable subject matter. However, it is the considered opinion of our experts that this should indeed be workable and should lead to a result at the UKIPO which broadly corresponds to an assessment by the EPO. By endorsing the Duns principles and G1/19, the Court’s judgment does not leave the UKIPO much leeway to depart from the approach taken by the EPO. We feel this case will likely have a positive impact for patent applicants.
With a similar patentability analysis, patent applicants will have more legal certainty to select between filing at the EPO and the UKIPO. This upgrade should make the UKIPO more appealing to patent applicants than it was previously.
A final question IP professionals should be concerned with: will this decision change practice at the UKIPO, and does the judgment provide a justification for the UKIPO to refuse to search an invention? In our opinion, the UKIPO should now routinely perform a search for software patent applications. For example, when the EPO applies G1/19 in practice, the Guidelines for Examination state that finding the closest prior art and evaluating differences can help to determine if the identification of the technical character was done correctly. Therefore, EPO practice as set out in the Guidelines is a strong existing precedent for the UKIPO to respect, unless convinced that the EPO is wrong beyond the ambit of a reasonable difference of opinion.
In conclusion then, we think this decision brings the UK into closer alignment with the EPO on patentable subject matter, and presents a test for overall patentability that, whilst not completely identical to the EPO, should in practice be workable. On that basis the decision is very welcome.
Nick Wallin, Russell Barton, Harry Strange, Theo Worsley and Atheer Galdagon
This publication is a general summary of the law. It should not replace legal advice tailored to your specific circumstances.
© Withers & Rogers LLP February 2026
