1.1. Any third party – independent legal entity

In T 305/08 the appellant (opponent I) had filed an appeal against the decision of the opposition division to reject the opposition. Two separate interventions were subsequently filed (by opponents II and III), which also raised fresh grounds of opposition under Art. 100(c) EPC 1973. The board stated that the term "any third party" in Art. 105(1) EPC could not be given an interpretation other than that each party had to be a separate legal entity and that it was irrelevant whether they belonged to the same group of companies. Nor was allowing the interventions tantamount to allowing the appellant to late-file oppositions via opponents II and III under its control and thus introduce new evidence. The interventions were therefore admissible.

In T 384/15 two interventions were filed in the appeal procedure by different legal entities, both belonging to the same company. The respondent (patent proprietor) argued that there was credible evidence that the opponent was acting as a straw man on behalf of the company to which also the two interveners were inextricably linked. The board considered that there was no question that the interveners were third parties within the meaning of Art. 105(1) EPC, i.e. different legal entities, with respect to the opponent (appellant) regardless as to whether or not one of the interveners was the principal instructing the opponent (G 3/97, OJ 1999, 245). The board also rejected the argument that there had been an attempt by the opponent and the interveners to circumvent the law by abuse of process, since there was no proof that the opponent had acted directly on behalf of one of the interveners (T 305/08).

In T 1702/17 the board held that the only material issue when determining whether the interveners could be regarded as third parties was whether the appellant and the interveners were legally distinct companies and thus independent legal entities. Economic ties of any kind between the three companies (in the case in issue, the respondent had asserted that the relationship was as 100% subsidiaries of the appellant under its authority) were immaterial under the EPC as regards the admissibility of the interventions. Nor had there been any abuse of law. On the contrary, allowing third parties to assert new grounds for opposition and submit new documents as interveners with the aim of having the patent revoked was in keeping with the spirit and purpose of the provisions of Art. 105 EPC and thus the legislator's intent.

In T 435/17 the board held that a "third party" within the meaning of Art. 105(1) EPC had to be a separate legal entity from the other parties, and that there was no legal basis for excluding an intervener on the grounds that it shared premises, a current account for fee payments or a professional representative with an opponent.

In T 1891/20 an intervention was filed in the appeal procedure by a legal entity separate from appellant II. The respondent (patent proprietor) argued among other things that appellant II and the intervener had a common representative, who had made submissions in a single document which concerned both of these parties. The board referred to R. 151 EPC, according to which parties may appoint a common representative. The appointment of a common representative for two opponents was not different from the appointment of a common representative for an opponent and an intervener. In both cases, the commonly represented parties could be in a different situation as to the admittance of their submissions. This, however, did not prevent them from appointing a common representative. The board considered the intervener as a "third party".