In T 293/88 (OJ 1992, 220) the board found that the decision of the opposition division to revoke the patent without issuing any communication in advance disregarded the fact that the validity of the uncontested claims 7, 9 and 10 had not been challenged at all and that the parties reasonably ought to have been given a further opportunity to fall back on that position in such circumstances. The onus of raising such related additional matter with the parties was on the opposition division under Art. 113(1) EPC - which it had not done in this case (unlike T 9/87, OJ 1989, 438; here it was held that the opposition division had no obligation to examine uncontested claims in different categories which related to different inventions).
In T 558/95 the opposition division had issued two written communications before the oral proceedings stating that, "in the provisional opinion of the opposition division", the subject-matter described in the public prior use did not prejudice the contested patent within the terms of Art. 100(a) EPC. The patent proprietor therefore found it "surprising" that detailed consideration was given to the public prior use during the oral proceedings. However, the board held that provisional opinions of this kind were not binding on the further proceedings. Especially in view of the fact that the opponent continued to elaborate his arguments against these comments by the opposition division, the possibility of a different assessment by the opposition division could not be ruled out from the start.
The opposition division that rejects an opposition as inadmissible without providing a reasoning prior to its decision prevents the opponent from responding with comments, thus violating the right to be heard (T 1056/98).
Normally, where a document has been sent to one of the parties, that party is given sufficient time to respond thereto before a department of the EPO takes a decision (T 263/93). If the case is to be remitted to the department of first instance for further prosecution, the recipient of a document still has, in view of the remittal, the opportunity to contest the arguments put forward by the other party for the purposes of the remitted case (see T 832/92).
Under Art. 113(1) EPC, the opposition division must expressly give the parties an opportunity to present observations after remittal to it of a case by a board of appeal for further prosecution on the basis of new evidence, even if submissions with respect to this new evidence have already been made during the preceding appeal proceedings (see T 892/92, OJ 1994, 664; see also T 769/91). In T 120/96 another board shared this view and added that the term "opportunity" in Art. 113(1) EPC could only be given effective meaning by applying the principles of good faith and the right to a fair hearing. For such an opportunity to exist, it is necessary that the parties be expressly asked whether or not they wish to present, within a fixed period of time, their comments, or if, as in the case at issue, the parties have already made detailed submissions during the previous appeal proceedings, whether or not these submissions should be regarded as complete. On these grounds alone, the board found that the immediate termination of the opposition proceedings following the remittal, without any intervening communication announcing the resumption of proceedings, was inconsistent with Art. 113(1) EPC.