In G 3/97 and G 4/97 (OJ 1999, 245 and 270) it was held that the legislator explicitly designed the opposition procedure as a legal remedy in the public interest which, according to Art. 99(1) EPC, is open to "any person".

According to the Enlarged Board, an opponent's status is a procedural status, and the basis on which it is obtained is a matter of procedural law. This is addressed in Art. 99(1) EPC in conjunction with Art. 100 EPC 1973, R. 76 and R. 77(1) EPC (R. 55 and R. 56(1) EPC 1973). The opponent is the person who fulfils the requirements set out therein for filing an opposition; in particular the person must be identifiable (R. 76(2)(a) EPC, R. 41(2)(c) EPC; R. 55(a) EPC 1973; see also in this chapter IV.C.2.2.4). The EPC does not specify any further formal conditions to be met by the opponent. A person who fulfils the said requirements becomes a party to the opposition proceedings (Art. 99(3) EPC; Art. 99(4) EPC 1973).

Thus, the EPC does not require that the opponent have his own interest in the outcome of the opposition proceedings. As early as in G 1/84 (OJ 1985, 299) the Enlarged Board held that the motives of the opponent were in principle irrelevant (otherwise, no doubt, the phrase "any person" would have been rendered as "any person interested"), whilst his identity was primarily of procedural importance (similarly in T 635/88, OJ 1993, 608; T 590/93, OJ 1995, 337). Following that case law, the board in T 798/93 (OJ 1997, 363) found that the EPC and its attendant provisions contained no requirements as to the opponent's personal circumstances or motives for acting. Requests for the opposition to be declared inadmissible therefore had to be refused if, as in the case under consideration, they were based on either an objection regarding a particular aspect of the opponent's status, such as his profession (professional representative before the EPO) or his field of technical expertise (different from that of the opposed patent), or on his lack of motives for acting (statement by the opponent saying that his only reason for acting was to complete his training).

According to T 353/95, only an existing natural or legal person can be a party to opposition proceedings and this applies also at the appeal stage since Art. 107, first sentence, EPC makes no different provision (R. 66(1) EPC 1973; R. 100(1) EPC).