On appeal from: [2009] EWCA Civ 1062

The Court unanimously overruled a line of cases which held that a patentee, whose patent (in proceedings against a particular defendant) was found to be valid and infringed, was entitled to claim damages from the defendant for the infringement without regard to a subsequent revocation of the patent, even though as a matter of English law the revocation of a patent for invalidity related back to the date of grant. The major fallacy in this line of cases was the assumption that cause of action estoppel was absolute generally rather than absolute only as regards points actually determined by the earlier decision. Accordingly, where judgment was given in an English court that a patent (whether English or European) was valid and infringed, and that patent was subsequently revoked or amended (whether in England or at the EPO), the defendant was entitled to rely on the revocation or amendment on the enquiry as to damages.

For judgment, please download: [2013] UKSC 46
For Court’s press summary, please download: Court’s Press Summary
For a non-PDF version of the judgment, please visit: BAILII