T 0296/93 (HBV antigen production) vom 28.07.1994

The applicable starting point for calculating the three month period for intervention under Article 105(1) EPC is always the date of the institution of the first court action. Where a court action for infringement was first brought by a patentee against an alleged infringer, Article 105(1) EPC first sentence applies, even though the latter later instituted a court action seeking a declaration of non-infringement under Article 105(1) EPC second sentence, with regard to the same patent.