In this Court of Appeal decision, the court held: (i) that AI is not a person and cannot be an inventor under the 1977 Patents Act and; (ii) (Birss LJ dissenting) that Dr Thaler failed to comply with the obligations of s13(2)(a) (identifying a person as the inventor) and s13(2)(b) (indicating how the applicant derived the right to be granted a patent) in his patent application by listing DABUS (an artificial intelligence (AI) machine) as the inventor and claiming entitlement to a patent on the basis of ownership of that AI. As a result, the patent application was correctly deemed withdrawn.

An application to the Supreme Court is likely but whether such an application will be accepted may depend on the status of the currently ongoing legislative review concerning AI and the law.


In 2018, Dr Thaler made two patent applications, listing DABUS as the inventor. In his initial application, Dr Thaler described his right to be granted the patent as deriving from "ownership of the creative machine 'DABUS'" and in a later amendment noted "the applicant identified no person or persons whom he believes to be an inventor as the invention was entirely and solely conceived by DABUS".

The Comptroller held that Dr Thaler failed to comply with section 13(2) of the Patents Act 1977 (PA 1977) by failing to: (i) identify the person believed to be the inventor (DABUS was not a person and could not be an inventor), as required by s13(2)(a); and (ii) adequately indicate where he derived his right to the Patent, as required by section 13(2)(b). This decision was appealed to the High Court and dismissed by Marcus Smith J ([2020] EWHC 2412 (Pat)) on the grounds that: (i) DABUS could not be an inventor because it was not a person; (ii) Dr Thaler had not established a right to be granted the patent; and (iii) as a result, the Comptroller was correct to find the applications were deemed withdrawn under s13(2).


This judgment relates to Dr Thaler's further appeal to the Court of Appeal. The core issues were:

  1. Whether the 1977 Act required an inventor to be a person;
  2. Whether Dr Thaler was entitled to apply for and be granted a patent and what function s13(2) PA 1977 served; and
  • Whether the Comptroller was correct in finding the application was deemed withdrawn under s13(2)?

The presiding judges (Birss LJ, Laing LJ and Arnold LJ) agreed on the first issue: PA 1977 requires an inventor to be a person and thus DABUS, the AI machine, cannot be an inventor.

The second issue involved two separate limbs. The first was whether Dr Thaler was entitled to apply for (and be granted) a patent under s7 PA 1977. Section 7 provides that while "any person" can apply for a patent (s7(1)), a patent can only be granted to inventor(s) or others in the circumstances provided for in s7(2). The second limb related to the effect of s13(2) which requires an applicant to identify the person(s) s/he believes to be the inventor (s13(2)(a)) and, where the applicant is not the inventor to indicate the derivation of her/his right to be granted the patent (s13(2)(b)). The consequence of a failure to comply with s13(2) is the deemed withdrawal of the patent application (the third issue).

The judges disagreed about the second and third issues.

Arnold LJ

Arnold LJ first considered whether Dr Thaler was entitled to apply and be granted a patent under s7. Since Dr Thaler accepted he was not the inventor (s7(2)(a)) nor a successor in title (s7(2)(c)), Arnold LJ focused on whether Dr Thaler was entitled to be granted the patent by virtue of a rule of law (s7(2)(b)), namely by exclusive possession through his ownership of DABUS. Arnold LJ noted that "an invention is a piece of information": the inventions created by DABUS were new intangibles produced by Dr Thaler's tangible asset (DABUS). Arnold LJ concluded that the law of exclusive possession did not apply because there is no rule of law that a new intangible produced by existing tangible property is the property of the owner of the tangible property". He continued that there is "no rule that the property contemplated by section 7(2)(b) in an invention created by a machine is owned by the owner of the machine" and thus Dr Thaler was not entitled to be granted a patent.

Arnold LJ also considered the function of s13(2) and the role of the Comptroller. Referring to Nippon Piston Ring Co's Application [1987] RPC 120, Arnold LJ held that the Comptroller's role under section 13 is "to check whether the prescribed statements have been filed in time, and if so whether the statements filed appear to comply with the statutory requirements or are defective on their face". He concluded that Dr Thaler did not identify the person he believed to be the inventor and instead "deliberately identified a non-person as the inventor" which Arnold LJ described as "a legal impossibility". Arnold LJ also concluded that Dr Thaler did not identify how his claimed right to be granted a patent was derived, instead merely asserting that it was sufficient that he owned DABUS. Arnold LJ held this assertion to be inadequate as a matter of law (for the reasons set out above).

Therefore, on the final issue, Arnold LJ concluded that the Comptroller was correct in finding the application was deemed withdrawn under s13(2).

Laing LJ

Laing LJ considered the issues of whether Dr Thaler was entitled to apply for and be granted a patent under section 7 and the function of s13(2) PA 1977 together. She reasoned that s7 is the only provision of the 1977 Act which confers a right to apply for a patent. She noted that "on its proper construction, it does not permit the grant of a patent in a case in which the inventor is not a person". She commented that "the effect of section 7(2)(a) is that the inventor must be a person. Only a person can make, before the invention is made, an enforceable agreement by which he is entitled to the whole of the property in the invention (other than equitable interests). Such an agreement can only be made with another person. Only a person can have a successor in title (section 7(2)(c)). It follows that, absent a statutory deeming provision, it is simply not possible, as a matter of law, for Dabus to be an 'inventor' for the purpose of section 7." She also agreed with Arnold LJ that Dr Thaler could not be entitled by any other rule of law.

On this basis, Laing LJ approached the question of whether Dr Thaler had complied with the obligations under s13(2). She concluded no because Dr Thaler "positively assert[ed] that the inventor [was] not a person" and thus failed to comply with section 13(2)(a) and further provided no basis to derive a right as required by section 13(2)(b). As a result, the Comptroller was right to deem the application withdrawn.

Birss LJ (dissenting)

In considering whether Dr Thaler was entitled to apply and be granted a patent under s7, Birss LJ suggested that the starting position was that Dr Thaler (as the applicant) was presumptively entitled. He explained that section 7(4) provides the presumption that the person making the application shall be taken to be the person entitled to be granted a patent and should be interpreted as applying "except in so far as the contrary is established in proceedings constituted for that purpose in this Act', i.e. in proceedings under s8 and s37 [proceedings on entitlement]". Applying this presumption, he suggested that although Dr Thaler could not apply for the patent under s7(2)(a) (as the primary or joint inventor) or s7(2)(c) (as a successor in title), which involved a transfer of rights, he could under s7(2)(b) as the right's first owner (as soon as the patent came into existence) as comparable to an employer for employee inventions.

On the issue of the of the effect of s13(2) and role of the Comptroller, Birss LJ referred back to the legislative history (going back to the Statute of Monopolies of 1623), Birss LJ suggested that the purpose of s13(2) is to provide information to be made public. Birss LJ explained that that 1977 Act does not provide the Comptroller with the power to determine the question of who has the right to be granted a patent and thus was not in a position to assess whether Dr Thaler's claim to derivation was adequate. He noted that the consequence of failing to comply with section 13(2) was deemed withdrawal of the application. He explained this was not consistent with the idea that the Comptroller makes decisions on the merits of applicants' entitlement.

Regarding the requirement to identify the inventor, Birss LJ interpreted s13(2) to mean that bona fide errors in identifying inventor(s) or derivation should not prevent applicants from being granted patents or expose patents to revocation. He commented that "all that is required in relation to inventorship is that the applicant must identify who he believes is the inventor". He explained that an application would unlikely be prejudiced if, in good faith, an applicant was unable to identify the inventor. He reasoned that if the "Comptroller was satisfied that what the applicant had provided was their genuine belief, then it seems to [him] that section 13(2)(a) has been satisfied. There is no reason to read the section as imposing any higher obligation on an applicant than to state their genuine belief about who the inventor was". He concluded that by listing DABUS as the inventor based on his genuine belief, Dr Thaler complied with section 13(2)(a).

Turning to s13(2)(b), Birss LJ concluded, on the basis of his conclusions on s7(2)(b) that, by listing his ownership of DABUS as the basis of his right to the patent, Dr Thaler satisfied this requirement.

On this basis of the reasoning above, Birss LJ concluded that Dr Thaler had complied with s13(2)(b) and that the Comptroller was wrong to deem the application withdrawn.


This judgment reaffirms that an AI machine cannot be an inventor: the current law requires any inventor to be a "person" which AI is not. For an AI machine to ever be listed as the inventor on a patent, and for its operator to apply for such a patent, legislative changes are required unless the Supreme Court overturns the Court of Appeal's finding that an inventor must be a "person", which appears unlikely (this was a unanimous decision).

The more interesting and, arguably unresolved issue in light of the contrasting decisions of Birss LJ and Arnold LJ, is whether Dr Thaler complied with the requirements of section 13(2). This is a complex issue of statutory interpretation on which two specialist patents judges (Arnold LJ and Birss LJ) reached opposing views. Arguably, it is unfair that an applicant who compiles with the patent bargain should be deprived of protection due to a formality. Indeed, the consequence may be that the owners of AI will keep their inventions secret and seek to avail themselves of the section 64 prior use defence if a patent covering the invention is subsequently granted. Alternatively, AI output, if churned out into the vast public repository of the internet, will become a source of prior art that invalidates (later, perhaps independent) inventive contributions of real people.

Birss LJ's suggestion that the requirement to list an inventor is satisfied if the applicant had "genuine belief" about who they list as the inventor is an appealing way to resolve the issues without full scale legislative review. He reasons this by a comparison to employee inventions (although not rooted in a comparable statutory regime) as a basis for concluding that the right to apply for a patent for an invention created by AI could be rooted in s7(2)(b) and his interpretation that the 1977 Act does not provide the Comptroller with the power to determine the question of who has the right to be granted a patent (and thus is not in a position to assess the adequacy of Dr Thaler's indicated derivation of a right to apply).

This issue may be appealed to the Supreme Court and could go either way. However, given the ongoing review of issues regarding AI by the UKIPO, it seems more likely that change will come in the form of revisions to legislation.

Finally, although not central to this decision, it is also interesting to recognise that both Birss LJ and Arnold LJ acknowledged the tension between AI inventions and the test for inventive step. Birss LJ noted, "there is now a class of potentially patentable inventions which can be created without a human inventor then this does not mean that [the objective standard of a notional person skilled in the art] could not be applied to consider whether the invention satisfies the [inventive step] test." This raises the question of whether in future the skilled team could be held to include notional skilled persons with access to the output of AI.

The court's consideration of AI in the context of patent cases is in its infancy. It remains to be seen how the court will address the plethora of issues to come. Regardless of whether DABUS was or was not the devisor of any patentable inventions, this judgment has highlighted the fact that the current statutory framework does not cater for the possibility that an AI machine may be able to invent. The legislative review concerning AI and the law is therefore to be welcomed.

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