For many software developers, the UK patent system has long been tricky to navigate.

Various items are excluded from being patentable inventions, including:

  • Programs for computers;
  • Discoveries, scientific theories and mathematical methods;
  • Aesthetic creations;
  • Schemes, rules and methods for performing mental acts, playing games or doing business;
  • Presentation of information.

These exclusions apply as per Section 1 of the Patents Act 1977 and article 52 of the European Patent Convention (EPC) where the patent relates to one of the above ‘as such’.

A decisive shift away from Aerotel

For nearly 20 years, Aerotel has dominated the UK approach to the computer program exclusion — requiring courts and the UKIPO to focus on whether an invention made a novel ‘technical contribution’ to the known art but automatically excluding any invention which was a ‘computer program as such’.

Now, after the Supreme Court unanimously allowed Emotional Perception AI Ltd’s appeal, it has held that the four‑step test laid down in Aerotel should no longer be followed.

It concluded that this approach misinterpreted Article 52 of the European Patent Convention, which sets the threshold rules on what qualifies as a patentable ‘invention’, including the exclusion for computer programs ‘as such’.

In particular, it wrongly conflated the threshold question of whether there’s an ‘invention’ with later questions of novelty, inventive step and industrial application. Those are separate and independent requirements and should not be mixed together.

Return of the ‘any hardware’ approach

In place of Aerotel, the court endorsed the EPO’s ‘any hardware’ approach, as most recently affirmed by the Enlarged Board of Appeal in G1/19 — a leading EPO decision confirming that computer‑implemented inventions involving any technical means are not excluded ‘as such’.

Under this approach, a claim will qualify as an ‘invention’ for Article 52 purposes if it has technical character, which is satisfied if it involves the use of any technical means or hardware, however ordinary.

This sets a deliberately low bar at the eligibility stage. The Court accepted that this reflects the wording of Article 52(3), which excludes subject matter only “as such”.

The Court of Appeal’s decision in Emotional Perception AI had determined that systems using artificial neural networks (ANNs) sit squarely within the exclusion for “programs for computers … as such’.

The Supreme Court confirmed that ANNs are ‘programs for computers’ within the meaning of Article 52(2)(c).

An ANN was characterised as an abstract computational model comprising network topology, weights, biases and activation functions that instructs a computer to process data in a particular way.

The court rejected arguments that ANNs escape the exclusion because they’re implemented in hardware, trained by data (rather than coded by humans) or operate in parallel rather than through traditional ‘if-then’ logic. None of these features prevented an ANN from being a program for a computer.

That conclusion, however, was concerned only with how an ANN should be categorised and did not determine whether the claimed invention was excluded as a “computer program as such”.

Crucially, however, the Supreme Court held that this was not the end of the analysis. Although the invention involved a computer program, applying the ‘any hardware’ approach meant that it was not excluded as a computer program ‘as such’.

Although the invention involved an ANN (acknowledged to be a computer program), it also involved technical means including computer hardware, databases, networks and user devices.

The Supreme Court found that: “It is beyond dispute that on this approach the claims are to an ‘invention’ and are not excluded by article 52(2)(c).

Although the claimed method involves an ANN which is a program for a computer, it also involves technical means because the ANN can only be implemented on some form of computer hardware.

In addition, the claims refer to a database for storing data files, a communications network and a user device – all of which require or constitute hardware.

That is sufficient to show that the subject matter of the claims has technical character and is not to a computer program ‘as such’.

The Supreme Court was not suggesting that computer programs are no longer excluded as a class but rather that the exclusion applies only where the claimed invention amounts to nothing more than a computer program.

Where the invention, taken as a whole, involves technical means (such as requiring or constituting hardware), that’s sufficient to show that the subject matter has technical character and is capable of qualifying as an ‘invention’ under Article 52.

The UKIPO was therefore wrong to refuse the application solely on the basis of the computer program exclusion.

The new intermediate step

The court emphasised that clearing the requirements of Article 52 does not mean that an invention is patentable.

Following G1/19, there’s now an ‘intermediate step’ between eligibility and inventive step.

At this stage, decision‑makers must identify which features of an invention contribute to the technical character of the invention as a whole. Features that do not make such a contribution are filtered out and ignored when assessing novelty and inventive step.

The Supreme Court confirmed that UK law need not adopt the EPO’s problem‑and‑solution approach wholesale and may continue to apply the Pozzoli framework.

This is the established UK approach to assessing inventive step (by asking whether the claimed technical contribution would have been obvious to the skilled person), informed by this filtering exercise.

As the case had been argued throughout on the basis of Aerotel, the Court declined to apply the intermediate step itself and remitted the matter to the UKIPO.

Much will depend on how the UKIPO and courts apply this new approach in practice. While the adoption of the ‘any hardware’ test lowers the threshold for establishing an ‘invention’ under Article 52, it does not follow that all computer‑implemented inventions will be patentable.

Claims will still need to satisfy the requirements of novelty, inventive step and industrial application — and the invention must amount to more than a computer program in the abstract.

The new test for AI patentability 

Step 1: Is there an ‘invention’? (Article 52 EPC)

  • Does the claim, taken as a whole, involve any technical means or the use of any hardware?
  • If yes: the claim has technical character and is not excluded at the threshold stage (this does not determine whether a patent will be granted).

Step 2: Intermediate step (G1/19)

  • Which features of the claim contribute to the technical character of the invention as a whole?
  • Filter out (i) non-technical features that do not interact with the technical subject matter of the claim and (ii) technical features that do not contribute to the technical subject matter of the claim.

Step 3: Patentability assessment

  • Is the invention novel?
  • Does it involve an inventive step (applying the Pozzoli framework and considering only features that contribute to the technical character of the invention as a whole)?
  • Is it capable of industrial application?

Unlocking the door to UK patent protection

The Supreme Court’s judgment marks the end of UK exceptionalism in the treatment of AI and software patents. Eligibility is now easier to establish and UK practice is more closely aligned with the EPO.

While this is a significant step for developers, it does not mean that all software-based and AI patents will now be granted.

For innovators, success will depend on clearly identifying which aspects of a computer-related invention genuinely contribute to its technical character, are novel and can support an inventive step.

So, the door to UK patent protection has been unlocked for computer-related patents.

The floodgates could now open, particularly with the rise of AI – certainly, we now expect to see even more patent applications being filed and an increase in the number of successfully granted patents.

  • Colin Bell, a partner in Brabners’ intellectual property and technology teams, also contributed to the article