Is your AI patentable? Lessons from the Court of Appeal’s landmark ruling

As artificial intelligence (AI) advances at pace, it raises complex questions for intellectual property (IP) law. Could these innovations redefine what’s patentable? The Court of Appeal’s decision in Emotional Perception AI Limited (Appellant) v Comptroller General of Patents (Respondent) provides important clarity.

Here, Paddy Fearnon and Colin Bell explore the key issues from the case and consider the practical implications for those operating in the technology, creative and data-driven sectors.

Background 

Emotional Perception AI Ltd (EPAI) sought to patent a system that recommends media files like music tracks to users. The system’s novelty lay in its use of an artificial neural network (ANN) to recommend content based on human perception, rather than relying on traditional categories like genre. 

The dispute centred on section 1(2) of the Patents Act 1977 which excludes “a program for a computer… as such” and mathematical methods from patentability. The question — do ANNs fall within this exclusion?

What is an ANN?

An ANN is a type of machine learning model inspired by the way that the human brain processes information. It consists of layers of interconnected ‘neurons’ that process data by applying weights and biases to inputs and producing outputs. ANNs learn patterns through a training process, adjusting these weights to improve performance. Once trained, they can perform tasks such as recognising images, interpreting language or — as in this case — recommending media files based on perceived similarity.

The court’s key findings

1. ANNs are programs for a computer

The court held that both hardware and software ANNs are caught by the exclusion in section 1(2) of the Patents Act 1977. This is because the trained weights and biases function as instructions that tell the machine how to process information. Whether those instructions are written by a human or learned by a machine does not matter. Therefore, the ANN could not be patented. 

2. No technical contribution

A central issue was whether the invention made a ‘technical contribution’ beyond the excluded subject matter. The invention’s core purpose — recommending files based on meaning-based similarity — was deemed subjective and aesthetic, not technical. The use of technical tools like ANNs do not automatically make the contribution technical.

3. No legal distinction between hardware & software

The judgment clarified that — for the purposes of the exclusion — there’s no meaningful distinction between hardware and software ANNs. Both are treated as computers running a program and both are subject to the same legal analysis.

4. Mathematical method exclusion looms large

The court noted that — even if the ANN was not considered a ‘program for a computer’ — it could still fall under the mathematical method exclusion in section 1(2)(a) of the Patents Act 1977. Pure mathematical methods are not patentable unless they produce a technical effect like controlling a machine or improving system performance. In this case, the effect was limited to making recommendations based on emotional similarity which the court held was not technical.

Why this is a game changer

This ruling sends a clear message that AI inventions that hinge on subjective outcomes like emotional similarity will face an uphill battle for patent protection. It’s not enough to use innovative technology — the contribution must be technical in nature for patentability in the UK.

For innovators developing AI solutions, this means that:

• Claims must emphasise technical effects rather than aesthetic or cognitive outcomes.
• Alternative IP strategies such as trade secrets and copyright should be considered.
• Staying alert to evolving case law is imperative as what counts as ‘technical’ is under constant scrutiny.

Supreme Court appeal

EPAI was granted permission to appeal the decision to the Supreme Court with the hearing held on 21 and 22 July 2025.

The issues in question were:

“Does the statutory restriction on patenting a program for a “program for a computer…as such” apply to artificial neural networks (“ANNs”)? If so, does it prevent the Appellant’s application from being patented?”

Put simply, EPAI argues that its ANN has a technical contribution and technical effect and therefore should not be considered excluded matter. The company is asking the court to adopt an approach more similar to the European Patent Office (EPO) rather than the stricter stance taken by the UK Intellectual Property Office (UKIPO).

The decision is expected in the coming weeks, likely by the end of 2025 or early 2026, though historically decisions can take longer than expected. 

Talk to us

Our specialist IP lawyers will be monitoring the Supreme Court’s decision closely and will provide further updates in due course. With extensive experience in patent applications, disputes and all other areas of IP, we’re well placed to advise on how this ruling may affect your innovation strategy.

Talk to us by giving us a call on 0333 004 4488, sending us an email at hello@brabners.com or completing our contact form below.