Experiments in the Patents County Court: when are they allowed?

Sitting in the Patents County Court for England and Wales, Judge Birss QC laid down some helpful guidance late last month on the use of experimental evidence in patent litigation in that court.  This guidance can be found in Liversedge v Owen Mumford Ltd and another [2011] EWPCC 34, in which the judge allowed limited experimental evidence to be used in a dispute which concerned a patent for the Humira Pen, an auto-injector device for delivering a drug, where that evidence went directly to the issue of infringement and thus satisfied the cost-benefit test which was now applied in proceedings litigated before that court. At paragraphs 25 to 26 he said:

"The decisive factor to my mind is that the experiments go directly to the question of how the product alleged to infringe actually works. It may be that the correct construction of the claim means that the product infringes either way, regardless of the dispute about how it works. However when I raised the question of whether I should direct a preliminary issue on the question of construction there was no enthusiasm for that course from either side. In my judgment the functioning of the Humira Pen is likely to be a crucial issue in this case.

Ms May submitted that a party is entitled to prove its case in the best way it can so long as it is reasonable and proportionate in the context of the case as a whole. In my judgment that formulation is capable of leading to trouble in relation to the Patents County Court procedure. To say that a party is entitled to prove its case the best way it can subject to caveats puts the matter the wrong way round. The purpose of the Patents County Court procedure is to facilitate access to justice, in part by streamlining and controlling what is admitted into the proceedings. Experiments are capable of becoming an expensive distraction in patent litigation unless they are kept under control. What is reasonable and proportionate is always important. Seeking to justify potentially complex evidence on the basis that it is the best evidence is a path which leads to increases in cost and time. In my judgment in this case the experiments are not complex at all. The claimant may succeed in showing they are entirely worthless but that is different from saying that they are complex or costly. They will be admitted because they satisfy the cost-benefit test".