Landmark UK Supreme Court Judgment Reshapes Patent Law For AI And Software Inventions

In a landmark decision, the UK Supreme Court has fundamentally reshaped the legal framework for patenting computer-implemented inventions, particularly those involving artificial intelligence. 

The Court has abandoned the long-standing Aerotel test, aligning the UK with the European Patent Office's (EPO) approach and opening a clearer path to patentability for AI and software  innovations.

In relation to the case Emotional Perception AI Ltd v Comptroller General of Patents, Designs and Trade Marks [2026] UKSC 3, the Court has abandoned the long-standing Aerotel test, aligning the UK with the European Patent Office's (EPO) approach and opening a clearer path to patentability for AI and software innovations.

For further background on this case, see our earlier article on the Court of Appeal's decision in Emotional Perception.

Key takeaways at a glance

• The Aerotel Test is Overruled: The four-step Aerotel test, which has been the cornerstone of UK practice for assessing the patentability of computer programs since 2006, is no longer good law.
• UK Adopts EPO's G1/19 Approach: The UK will now follow the EPO's more pragmatic, two-stage approach. The initial hurdle for patent eligibility is now significantly lower.
• AI is Officially a "Computer Program": The Court has clarified that an Artificial Neural Network (ANN) is, in legal terms, a "program for a computer."
• A Clearer Path to Patentability: Despite being a computer program, an AI-based invention will not be excluded from patentability "as such" if it is implemented on technical hardware. The focus now shifts from eligibility to the assessment of inventive step.

What has changed?

The end of the Aerotel era

The Court rejected the Aerotel test because it conflated the initial question of whether there is an "invention" with the separate requirements of novelty and inventive step. This created uncertainty and was inconsistent with the European Patent Convention (EPC). The new approach, adopted from the EPO's Enlarged Board of Appeal decision G1/19, simplifies the initial assessment:

• Stage 1 (The "Any Hardware" Test): Does the invention involve technical means (e.g., a computer, a network, a user device)? If yes, it is considered an "invention" and is not excluded from patentability at this stage. This is a very low bar to clear.
• Stage 2 (The "Intermediate Step"): Before assessing for an inventive step, the invention's features must be filtered. Only those features that contribute to the technical character of the invention as a whole are considered. Non-technical features are disregarded unless they interact with technical features to solve a technical problem.

The legal status of an ANN

The Court provided crucial clarity on the nature of AI. It concluded that an Artificial Neural Network (ANN) is not a physical machine but an abstract mathematical model that functions as a "program for a computer." This is because the ANN as a whole—its architecture, weights, and functions—constitutes a set of instructions that directs a computer to process data. This holds true whether the ANN is implemented in software on a general-purpose computer or "hard-wired" into dedicated hardware.

What this means for innovators and businesses

This judgment is a significant and positive development for the UK's technology and AI sectors.

Lower barrier to entry

It is now easier to pass the initial patent eligibility hurdle for software and AI inventions. The focus will no longer be on complex arguments about whether the "contribution" is technical, but on whether the invention is implemented using any hardware.

Focus shifts to Inventive Step 

The critical battleground for patentability will now be the assessment of inventive step. Innovators must clearly demonstrate that their invention provides a non-obvious technical solution to a technical problem.

Harmonisation with Europe

This decision brings the UK into closer alignment with the EPO, allowing companies to adopt a more unified patent strategy across the UK and Europe.

Patent application drafting is crucial

To succeed, patent applications for computer-implemented inventions must now be drafted to:

1. Clearly identify the technical hardware used.
2. Isolate the features of the invention that provide a technical effect.
3. Frame the invention as a technical solution to a technical problem, ensuring that non-technical business aims are shown to serve a technical purpose.

In conclusion, the Supreme Court's decision provides welcome clarity and modernises UK patent law to better accommodate the realities of AI and software development. While the path to a granted patent still requires demonstrating a genuine technical invention, the initial barriers have been lowered, creating a more favourable environment for protecting innovation in the UK.

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