Chemical patent infringement claim. ICI: valid patent had not been infringed. Imperial Chemical Industries v Montedison (UK) & Anor (1995). (CA (Stuart-Smith LJ, Morritt LJ, Sir John May) 7/3/95)
Summary: Claim for infringement and counterclaim for invalidity of plaintiff's patent.
Plaintiff's appeal from dismissal of its claim for infringement of Patent No.1,493,393. In the action the defendants accepted they had carried out the actions alleged to amount to infringement but by their defence denied patent infringement and counterclaimed for its revocation. The issues before the judge involved the construction of the patent and whether it was invalid for lack of a fair basis or ambiguity in infringement. The judge decided the issues of construction, save for one in favour of the plaintiff. He rejected the defence and counterclaim based on invalidity but was unable to determine whether the defendant's product, 'Velite', was an infringement and accordingly, since the burden of proof was on the plaintiff and the plaintiff had failed to discharge it, the claim failed. An application was made by the plaintiff to adduce the evidence of Professor Andrews in support of its appeal.