In Pozzoli SPA v (1) BDMO SA and (2) Moulage Industriel de Perseigne SA1, the Court of Appeal has restated and elaborated on the Windsurfing test for assessing obviousness, clarified the impact of overcoming a "technical prejudice" on patent validity, and quashed the notion that the TRIPS Agreement provides patentees with an automatic right of appeal if their patent is found invalid at first instance.


Pozzoli is an Italian company specialising in the manufacture and distribution of packaging for CDs and DVDs. It owned a European patent (UK) for a container that was capable of holding two or more discs, particularly compact discs, arranged so that the discs overlapped, were held by their centres and could be removed immediately.

The defendants manufacture and distribute a product which Pozzoli claimed infringed its patent. At first instance, Lewison J held that Pozzoli's patent was invalid for obviousness.2 Pozzoli applied to the Court of Appeal for permission to appeal from the first instance decision. The Court of Appeal granted permission to appeal but upheld Lewison J's decision.

Does the TRIPS Agreement provide patentees with an automatic right of appeal?

Pozzoli argued that Article 32 of the TRIPS Agreement imposes an obligation to grant permission to appeal where a patent has been revoked at first instance, even if there is no real prospect of success. Article 32 of the TRIPS Agreement reads: "An opportunity for judicial review of any decision to revoke or forfeit a patent shall be available".

The Court of Appeal dismissed Pozzoli's argument that Article 32 requires a full judicial hearing on the merits. It held that a decision by the Court of Appeal as to whether or not to grant permission to appeal from an order for revocation is a "judicial review" within the meaning of Article 32 of the TRIPS Agreement.

When should permission be granted?

The Court of Appeal went on to observe that, in patent cases which are not very clear and which would not be understood sufficiently readily by the Court of Appeal in an hour or so, the better course was normally for the trial judge to grant permission to appeal. This was because the Court of Appeal, when faced with an incomplete understanding of the case and a plausible skeleton argument seeking permission to appeal, would be likely to grant permission in any event.

The Windsurfing questions restated

The approach used to determine whether or not a patent is obvious was laid down by Oliver LJ in Windsurfing.3

In Pozzoli, the Court of Appeal restated the test as follows:

  • (a) Identify the notional "person skilled in the art";
  • (b) Identify the relevant common general knowledge of that person;
  • Identify the inventive concept of the claim in question or if that cannot readily be done, construe it
  • Identify what, if any, differences exist between the matter cited as forming part of the "state of the art" and the inventive concept of the claim or the claim as construed;
  • Viewed without any knowledge of the alleged invention as claimed, do those differences constitute steps which would have been obvious to the person skilled in the art or do they require any degree of invention?4

The key change is in the order of Oliver LJ's first two questions, making it clear that the inventive concept should be identified through the eyes and understanding of the skilled man

The Court of Appeal also observed that what had to be considered was the inventive concept of the claim in question, not some generalised concept derived from the specification as a whole.5 Where it is not possible for the parties to agree on the inventive concept of a claim or to précis the claim (for example, where there is a claim to a class of chemicals), the sensible way is to proceed and work on the features of the claim. In the end what matters is/are the difference(s) between what is claimed and the prior art.

Technical prejudice

When defending their patent against the allegation that it is obvious, patentees sometimes run the argument that there was a technical belief at the relevant date that deterred the skilled person from pursuing a particular path (a "lion in the path") and that the patent reveals that their belief was mistaken.

The Court of Appeal confirmed that the grant of a patent may be justified where the patent demonstrates that an established prejudice (i.e. one that is common general knowledge) is unfounded. In such circumstances there are two aspects to the state of the art, namely (i) the idea itself; and (ii) the prejudice that it would not work or would be impractical. As stated by Jacob LJ:

"Patentability is justified because the prior idea which was thought not to work must, as a piece of prior art, be taken as it would be understood by the person skilled in the art." 6

Thus, when a patentee discloses that, contrary to the mistaken prejudice, the idea will work or is practical, his contribution will be novel and non-obvious; he has shown that the apparent lion in the path is in fact a paper tiger. Where a patentee merely patents an old idea thought not to work or to be practical, however, and does not explain how or why it does work or is practical, his patent contributes nothing to human knowledge; the lion remains at least apparent (it may even be real) and the patent cannot be justified.


This case is of importance due to the Court of Appeal's restatement of the Windsurfing test and its clarification of how to determine the "inventive concept". The judgment also makes it clear that the "technical prejudice" line of defence to an obviousness attack will only be successful where the patent contributes to human knowledge by clearly disposing of the technical prejudice.

Although the Court of Appeal dismissed the argument that Article 32 of the TRIPS Agreement provides an automatic right of appeal against a decision revoking a patent, it has indicated that, in all but the clearest cases, leave to appeal should be granted by the trial judge.