Charlotte May QC appeared for the defendants in this patent infringement and validity trial. The patent in issue concerned the expiratory limbs of breathing circuits, and in particular the use of breathable materials to reduce or eliminate condensation.
The defendants admitted that their products fell within the claims of the patent in issue and counterclaimed for the revocation of the patent. The counterclaim was on the basis of anticipation and obviousness over the prior art, and of obviousness for lack of a technical contribution or insufficiency for lack of enablement.
The defendants ran an effective squeeze argument that if the expectation of success from the prior art was absent or too low then the patent was insufficient because it provided no more teaching than the prior art, and argued that in relation to inventive step the Claimant could not legitimately rely on a perceived problem in implementing the prior art unless the patent showed how to overcome it. Ultimately the patent was held by Mr Justice Meade to be valid as amended and infringed.