3.2. Extent of opposition

Rule 76(1) EPC (Art. 99(1) EPC 1973) provides, inter alia, that "notice of opposition shall be filed in a written reasoned statement". R. 76(2)(c) EPC (R. 55(c) EPC 1973) requires the notice of opposition to contain, inter alia, "a statement of the extent to which the European patent is opposed" (see also in this chapter IV.C.2.2.6).

In G 9/91 (OJ 1993, 408) the Enlarged Board clarified that the power of an opposition division or a board of appeal to examine and decide on the maintenance of a European patent under Art. 101 and 102 EPC 1973 (now merged in Art. 101 EPC) depends on the extent to which the patent is opposed in the notice of opposition (R. 55(c) EPC 1973; R. 76(2)(c) EPC). However, this principle is subject to a restriction: even if the opposition is expressly directed only against the subject-matter of an independent claim in a European patent, claims which depend on any such independent claim can nonetheless also be examined as to their patentability if the independent claim is eliminated in opposition or appeal proceedings, provided that the validity of these dependent claims is put in doubt prima facie by the information which is already available (see also T 443/93, T 31/08; the principles set out in G 9/91 have been followed by subsequent case law, e.g. T 1019/92, T 1066/92, T 711/04, T 1350/09; see also T 525/96 and T 907/03 in respect of claims of an auxiliary request).

If in a request the claims against which the opposition was directed have been deleted, that request and its subject-matter are allowable, because they are not a subject of the opposition proceedings (see e.g. T 2278/14).

The statements in the notice of opposition relevant to the extent to which the European patent is opposed should be interpreted in such a way that an addressee would understand them, taking into account the surrounding circumstances (T 376/90, OJ 1994, 906; see also T 1/88, in which the board based its interpretation of equivocal procedural acts on the "objective value of the declaration"; for a case where the accompanying letter contradicted the indication in Form 2300, see T 570/14).

In the light of G 9/91, the board in T 376/90 doubted that the general practice of interpreting the absence of such statements as an indication of the opponent's intention to oppose the patent concerned in its entirety could be continued. See however also T 764/06, in which the board concluded from the absence of a statement under R. 55(c) EPC 1973 that the patent was opposed only to a certain extent that the patent in suit was opposed in its entirety.

In T 938/03 the board highlighted that the extent to which a patent was opposed did not depend on the second requirement under R. 55(c) EPC 1973 (R. 76(2)(c) EPC), namely the indication of the grounds of opposition and the facts, evidence and arguments in support of these grounds. Rather, the extent to which a European patent is opposed was exclusively determined by what has been implicitly (see T 376/90, OJ 1994, 906) or explicitly indicated (in the case at issue by ticking the relevant box in EPO Form 2300). See, however, the different opinion in T 737/92, requiring that claims are actually opposed, as distinct from being merely formally mentioned in the notice of opposition.

In T 809/21 the board, applying the principles of G 9/91, noted that the opposition division's discretion to extend the opposition to unopposed claims was limited to claims which, while not explicitly opposed, were dependent upon an opposed independent claim which falls in opposition or appeal proceedings. There was no legal basis for the EPO to deprive the proprietor of a patent comprising claims 1 to 7 only, which were not opposed, nor the subject of any other ongoing proceedings before the EPO. Where the patent was not opposed in its entirety, and where the opposition division decided that all of the proprietor's requests in relation to the opposed claims must fail, only the unopposed claims, which were not part of any opposition proceedings, were left standing. Hence, provided the requirements of R. 82(1) EPC were met, the patent may be maintained on the basis of the unopposed claims, irrespective of whether the proprietor had filed an explicit request for this during the proceedings. Such a request would, in fact, be superfluous, since the unopposed claims had been granted and were not the subject of any opposition. In the case in hand the board found the decision of the opposition division to directly revoke the only partially opposed patent in its entirety had to be considered a substantial procedural violation within the meaning of R. 103(1)(a) EPC.