Patent – Infringement. When considering, in a patents case, whether to strike out a claim for an Arrow declaration (that products were old or obvious at a particular date), a judge was not exercising his discretion. The Court of Appeal, Civil Division, held that the task, at the interim stage, was to determine whether the pleaded facts and arguments gave rise to a realistic claim for Arrow relief which should go to trial. The discretion to grant Arrow relief, based on the test of 'useful purpose' was that of the trial judge, not that of the judge hearing the strike out application.