“What is the State of the Art for the Purpose of an Obviousness Attack?” That’s the title of an article I wrote in 2012 (27 CIPR 385). The puzzle is this. Traditionally, under the old Act, the body of prior art which could be set up against the patent in an obviousness attack (the “state of the art”), included only the common general knowledge plus prior art which would be discovered in a reasonably diligent search directed to the problem at hand. But s 28.3, which codified the obviousness in the new Act, provides that the relevant information is that “disclosed before the claim date … in such a manner that the information became available to the public”. That includes all public prior art, not just prior art which would have been found in a reasonably diligent search. There is an open question as to whether s 28.3, which was generally thought to have simply codified the existing non-obviousness requirement, had extended the state of the art. In my article I concluded that “contextual and purposive considerations imply that s. 28.3 was not intended to change the law, and the state of the art remains limited to information that is reasonably discoverable,” but “the argument based on the text of the provision is sufficiently strong that case law directly addressing the question will be needed before the point can be considered settled.”
While a number of decisions under the new Act simply assumed that the relevant state of the art was the same as under the old Act, the first decision to address this question directly, albeit briefly, was Novartis v Teva / deferasirox 2015 FC 770 blogged here, in which O’Reilly J held that indeed the law had not changed. (The question was noted, but not addressed, in 2015 FCA 163 .) Now, in Pollard v BABN, Locke J has suggested that he may prefer the opposite conclusion [192-95]. The question was relevant in respect of the Camarato application, which was crucial to the holding that Claim 1 was obvious. As I read his decision, Locke J never directly held that the state of the art extends to all publicly available prior art. Locke J noted the problem and made some comments on it, but his only direct holding was “Even if I was of the view that this reference’s findability in a diligent search was a relevant consideration, I would nevertheless conclude that it is citable for obviousness,” because it was indeed have been found in a diligent search, and so would be part of the state of the art under either test . The phrase “even if I was” is ambiguous. It might suggest that he was of the view and findability is not the test, and his holding that the Camarato application was findable was in the alternative; but it might also mean that it didn’t matter whether findability was the test, given that the reference was in fact findable.
Regardless of the precise holding, Locke J was clearly sympathetic to the argument that the state of the art should comprise all public prior art:
 [I]n order to obtain a valid patent, it is not enough for a skilled person simply to make an obvious change to what is known in the art. This principle should apply to any information that was available to the public, even if it would not have been located in a diligent search. For example, should a skilled person be able to obtain a valid patent by simply searching a dusty corner of a public library for a document that describes a forgotten invention and making an obvious change to it?
The problem with the final rhetorical question is that even under the traditional test a person cannot obtain a patent by “simply” searching a dusty corner and making an obvious change, because if the search was simple, by definition it would have been found in a reasonably diligent search. The proper question is whether a skilled person should be able to obtain a valid patent by making an obvious modification to a document that was found after a long and arduous search. The answer to that question is not so easy. The EWCA in Windsurfing  RPC 59, 71 made a very similar argument, which I discuss at more length in my article at 391-93.