In G 5/91 (OJ 1992, 617) the Enlarged Board of Appeal stated that, although Art. 24(3) EPC 1973 was only applicable to appeal proceedings, an objection on the ground of suspected partiality could also be disregarded at first instance if it had not been raised immediately after the party had become aware of the reason for the objection (or if it was based on nationality). The system might otherwise be open to abuse.

In T 49/11 after having received the summons which had made the parties aware of the composition of the board, the respondent filed two letters with the board before raising the partiality objection. In the first letter, the respondent had expressed its intention to speak German at the oral proceedings. The board held that such a statement constituted a procedural step within the meaning of Art. 24(3), second sentence, EPC, because it was a formal notification under R. 4(1) EPC. The partiality objection was therefore rejected as inadmissible. After analysing the text of Art. 24(3), second sentence, EPC in the three official languages (Art. 177(1) EPC), the difference between Art. 24 EPC 2000 and Art. 24 EPC 1973, and the transitional provisions of the EPC 2000, the board stated that it would have come to the same result under the old and the new text of Art. 24(3) EPC.

In T 1677/11 the board noted that the respondents had been aware of the closely related parallel appeal T 1760/11, which had been decided by a board in an identical composition one week previously, right from the beginning of the current appeal proceedings. Nevertheless, it was only after an adverse decision in that case had been announced that the respondents raised their objections of suspected partiality in the case at issue. The board stated that regardless of whether the respondents had taken a specific procedural step in the current appeal proceedings, they had not submitted their objection immediately after having become aware of the reasons. It held that, in view of the fact that the objections raised were linked to both appeals, attendance at oral proceedings in T 1760/11 had to be regarded, in the factual context of the case now at issue, as a procedural step within the meaning of Art. 24(3) EPC. Thus, the objections under Art. 24(3) EPC were rejected as inadmissible.

In T 1020/06 of 15 May 2009 date: 2009-05-15 the board held that filing new requests after proceedings under Art. 24(4) EPC 1973 had been started did not render the partiality objection inadmissible.

In T 49/15 respondent 4 argued that the board's decision to admit the appellant's new main request had been a prerequisite for its partiality objection because it had only been then that the appellant had been favoured. The board rejected this argument: a party did not have to be adversely affected by a board decision before it could cite suspected partiality as a reason for objection.