Sean Hutchinson

November 2025

Background

The growing use of artificial intelligence (“AI”) has had a significant impact on many parts of our daily lives, and patent law is no exception. Those interested in this subject will know that a patent applicant by the name of Dr Stephen Thaler once famously decided (controversially!) to name an AI system he had created (“DABUS”) as the inventor on several of his patent applications, and many courts around the world were thus forced to consider whether AI systems can be considered inventors, or whether inventorship is reserved for natural persons (i.e. human beings) instead.

The UK courts were no exception in this debate, with our Supreme Court holding at the end of 2023 that an AI system cannot be named as an inventor on a UK patent application (see our article of January 2024 for further details).

Despite the courts of several different countries deciding against Dr Thaler, recent developments on his patent applications continue to provide an invaluable source of case law, and thus we discuss one of these recent developments in more detail below.

Dr Thaler’s Divisional UK Patent Application

One of Dr Thaler’s UK patent applications was ultimately deemed withdrawn by the UK Intellectual Property Office (“UKIPO”) as a result of his having failed to file a statement of inventorship identifying a natural person as the inventor by the relevant deadline. However, there was a delay between that deadline expiring and the UKIPO deciding that Dr Thaler had failed to satisfy this requirement, and during the intervening period Dr Thaler filed a divisional patent application at the UKIPO. That divisional application was filed together with a statement of inventorship naming DABUS as the sole inventor and stating, in no uncertain terms, that Dr Thaler did not consider himself to be an inventor in this case.

All of these developments occurred before the above-mentioned UK Supreme Court decision. However, two days after that decision was issued, Dr Thaler filed a replacement statement of inventorship on his divisional application, this time naming himself as the inventor and explaining that whilst he did not consider himself to be an inventor “under traditional criteria”, the Supreme Court’s decision had led him to believe that he must be the inventor as the owner of DABUS.

The UKIPO, however, took a different view, objecting that Dr Thaler could not now claim to be an inventor having previously made clear that he was not. The UKIPO also indicated that Dr Thaler’s failure to file a statement of inventorship complying with the requirements of UK law on the parent application by the relevant deadline meant the parent application was deemed withdrawn when the divisional application was filed, which in turn meant the divisional application was not entitled to divisional status.

These developments ultimately led to the UKIPO deciding that Dr Thaler’s divisional application was to be deemed withdrawn as of the deadline for filing a statement of inventorship complying with UK patent law.

On Appeal: Decision of the High Court

Dr Thaler appealed this decision of the UKIPO to the UK Patents Court (part of the Chancery Division of the High Court).

On appeal, Dr Thaler argued the parent application should only have been deemed withdrawn as of the date on which the UKIPO decided he had failed to comply with the requirement to designate the inventor therefor, rather than the earlier date on which the deadline for filing the required statement of inventorship expired. This would have meant that the parent application remained ‘pending’ when the divisional application was filed, which would have resulted in the divisional application being entitled to divisional status. The High Court judge (Michael Tappin KC), however, disagreed, holding that there “is no reason to think that Parliament intended applicants to be able to delay the effects of their non-compliance until a final decision had been made confirming that they had not complied”. The judge thus quickly dismissed this argument of Dr Thaler and upheld the UKIPO’s decision to treat the divisional application as not being entitled to divisional status.

Dr Thaler also argued that, by failing to give the divisional application its divisional status, the UKIPO had effectively deprived him of his right to peaceful enjoyment of his possessions – that is, the so-called ‘right to own property’ enshrined in the Human Rights Act 1998 and the European Convention on Human Rights. Rather unsurprisingly, the High Court judge was quick to dismiss this argument, holding instead that rights in patent applications “are inherently limited and conditional”, and thus the human right upon which Dr Thaler attempted to rely was not applicable.

Dr Thaler additionally argued that the Supreme Court’s decision had caused his beliefs about the identity of the inventor to change. In other words, before the Supreme Court’s decision, he believed the inventor to be DABUS, however having read the Supreme Court’s decision he had been convinced that he was, in fact, the true inventor. The High Court judge, however, took a dim view of this argument, holding that the Supreme Court had only clarified whether an AI system can be named as an inventor on a UK patent application and had thus not changed the requirements for a natural person to be an inventor in any way. The High Court judge thus held it was not reasonable for Dr Thaler to assert that he now believed himself to be an inventor having previously emphasised so strongly that he was not an inventor, especially since he had highlighted in his replacement statement of inventorship that he continued to believe he was not an inventor “under traditional criteria”.

Finally, Dr Thaler argued that it was unclear to what extent a natural person must be involved in devising an AI-generated invention to be an inventor, and that he should not be penalised for having been transparent about how the invention was devised, noting that “an applicant [in his position] who had named themselves as inventor without disclosing the fact that the invention was generated by AI would have faced no objection from the UKIPO”. However, the judge declined to address these matters, holding instead that this was “not the occasion on which to embark on a discussion about what contribution is sufficient for a natural person to be an inventor of an AI-generated invention” and that it “may be that consideration should be given to whether provision needs to be made requiring an AI-generated invention to be identified as such (as the USPTO has done). But that is not a matter for me”.

The High Court judge thus dismissed Dr Thaler’s appeal in its entirety.

Conclusions

This decision of the UK High Court provides additional insight into the current state of UK patent law regarding AI-generated inventions.

Specifically, this decision highlights that, despite an applicant not being permitted to name an AI system as the inventor on their UK patent application, it is currently uncertain how much involvement the operator of the AI system must have in devising the invention to be the inventor instead. This in turn raises questions about whether anyone at all is entitled to be granted a UK patent for an AI-generated invention, which could have serious ramifications if left unaddressed, noting the rationale for granting patents is to promote the progress of technology.

The High Court decision also highlights that there may be compelling reasons for the UK to follow the example set by the United States Patent and Trademark Office (“USPTO”), namely by requiring AI-generated inventions to be identified as such in UK patent applications. However, the judge’s statements make clear that whether to make such a change to UK patent law is a decision for Parliament, not the courts.

The decision also has implications beyond AI-generated inventions, emphasising the importance of knowing the legal status of a parent patent application at the time of filing a divisional application, regardless of the nature of the claimed subject matter, to be confident that a divisional application is truly entitled to its divisional status.

We, along with many other patent attorneys working in the UK, look forward to seeing how these aspects of UK patent law develop.