Instruction Of Experts When Addressing Obviousness In The UK

One feature of UK patent litigation is the use of party-appointed experts to provide evidence to assist the Court when deciding issues in patent cases. On the question of obviousness, for example, the Court has to adopt the mantle of the person skilled in the art at the priority date, clothed with common general knowledge at that time, and decide (avoiding hindsight) whether the steps from the prior art to what is claimed involved an inventive step. In the 11 April 2016 judgment in American Science & Engineering Inc v Rapiscan Systems Ltd [2016] EWHC 756 (Pat) the judge commented on how the parties' experts were engaged. The Court provided guidance that the expert should not be shown the patent initially. The expert should first give their evidence on the common general knowledge of the person skilled in the art at the priority date; then be provided the prior art to comment on what it discloses; and then should be asked what steps it would be obvious to take in light of the common general knowledge. Once the expert has given that evidence, the patent may be provided to the expert. At that point, the expert can go back to address obviousness again, identifying points of difference between the prior art and what is claimed in the patent and answering whether those steps (without hindsight) involved an inventive step or were obvious.

Taking the approach identified by the Court may assist in avoiding criticism of the expert's evidence on obviousness. In some...