UK High Court endorses closest prior art approach

Vringo v ZTE

In a series of on-going court cases, Vringo (a so-called "patent troll") successfully defended the validity of a standards-essential patent relating to 3G communications and successfully sued ZTE (UK) for infringement of this patent ([2014] EWHC 3924 (Pat)).  In response to the infringement decision, ZTE (UK) sought to reopen the initial trial based on new prior art found after the trial judgment was handed down ([2015] EWHC 214 (Pat)).

Although the newly found prior art appeared potentially relevant to the validity of the patent, the court refused the request to reopen trial and rebuked ZTE (UK) for overlooking the decisive points of the case when preparing for the initial trial.  It was interesting to note the trial judge's comments regarding the selection of prior art when challenging validity, "Very many inventions are new combinations of old features. One item of prior art may disclose all but one of the claimed features, while another possible citation may disclose a different combination in which the missing feature is differentPart of the process of preparing a patent case as a challenger to validity is to identify this kind of art and make choices assisted by experts as to what citations to press at trial".

Readers will recognize that this is the “closest prior art” approach preferred by the European Patent Office and is another indication of the UK court's willingness to harmonize with European practice.