The general principle that nobody should decide a case in respect of which a party may have good reasons to assume partiality applies not only to the members of the boards of appeal according to Art. 24(1) EPC, but also to the members of the departments of the first instance of the EPO taking part in decision-making activities affecting the rights of any party (cf. G 5/91, OJ 1992, 617, G 1/05, OJ 2007, 362, T 433/93, T 95/04, T 283/03, T 1193/02).
In G 5/91 (OJ 1992, 617), the Enlarged Board of Appeal commented on the suspected partiality of a member of an opposition division. In the case which had led to the referral, T 261/88 (OJ 1992, 627), the primary examiner was a former employee of the opponent and had represented that company many times in examination and opposition proceedings before the EPO. The Enlarged Board observed that although the questions referred to it were directly related only to proceedings before an opposition division, the problems involved were of a general character and also had a bearing on the activities of the other EPO departments of first instance charged with the procedure, e.g. the examining divisions (see Art. 15 EPC 1973).
The Enlarged Board stated that it was clear that the provisions of Art. 24 EPC 1973 on exclusion and objection applied only to members of the boards of appeal and the Enlarged Board of Appeal and not to employees of the departments of the first instance of the EPO, including the opposition divisions. This distinction was intentional, as evidenced by the preparatory documents. The Enlarged Board of Appeal noted, however, that the fact that the special provisions of Art. 24 EPC 1973 do not apply to employees of the departments of the first instance of the EPO did not justify the conclusion that such employees were exempt from the requirement of impartiality. Even if very strict observance of this requirement was particularly important in proceedings before the boards of appeal and the Enlarged Board of Appeal in view of their judicial functions at supreme level within the European system of patent law, it had to be, as recognised by the President of the EPO, considered a general principle of law that nobody should decide a case in respect of which a party might have good reasons to assume partiality. The basic requirement of impartiality therefore applied also to employees of the departments of the first instance of the EPO taking part in decision-making activities affecting the rights of any party. However, it was to be noted that Art. 24(1) EPC 1973 contained some specific provisions aimed at safeguarding the impartiality and objectivity of members of the boards of appeal and of the Enlarged Board of Appeal, there being no equivalent provisions in respect of employees of the departments of the first instance. For example, while no member of a board of appeal could take part in an appeal if he had participated in the decision under appeal, it was clearly permissible under Art. 19(2) EPC 1973 for one member of an opposition division to have taken part in the proceedings for grant of the patent to which the opposition related. Thus, there was under the EPC in respect of employees of the departments of the first instance a certain flexibility which did not exist in respect of members of the boards of appeal and the Enlarged Board of Appeal, the basic requirement of impartiality nevertheless being in principle the same.
The Enlarged Board of Appeal also stated that the question whether or not an objection to a member of an opposition division on the ground of suspected partiality was to be considered justified could only be decided in the light of the particular circumstances of each individual case. Such considerations involved factual questions of degree rather than points of law and were therefore not a matter for the Enlarged Board of Appeal to decide.
In T 2291/08 a combination of a number of facts casted serious doubt on the impartiality of the opposition division. Such doubts were sufficient to declare the impugned decision null and void ab initio. The board considered it appropriate to recommend that the case be heard by an opposition division having different composition (in particular, Reason 23 of the decision).
With regard to the composition of the departments of first instance reference should be made to Chapter III.K.2).