Disqualifying partiality presumes that there is a preconceived attitude on the part of a deciding person towards a party to the case.
In T 261/88 of 16.2.1993 the board stated that when considering an allegation of partiality (in this case mainly based on the fact that the examiner was a former employee of the opponent), regard must be had to the particular facts of the case (cf. G 5/91). The board noted that the fact that the views held on the issues of the case by the examiner differed from those held by the party was itself not disqualifying. The board noted that disqualifying partiality was limited to situations where the opinion of a person responsible for taking decisions affecting the right of parties (e.g. a judge) was swayed by his attitude towards a party. The content of the file had to be examined to find out whether there were major deficiencies in the reasoning underlying the decision to such an extent that there was reason to believe that they were the result of a preconceived attitude.
The board examined whether the reasoning underlying the decision under appeal showed such major deficiencies that there was reason to believe that the primary examiner was, either deliberately or inadvertently, trying to "bend" the facts of the case, and that this had been done because of a preconceived attitude towards one of the parties. When the content of the file did not go beyond a normal discussion between the EPO and a party and there was nothing manifestly unreasonable to be found in the reasoning, disqualifying partiality could not be concluded. The board could not find anything basically or conspicuously wrong with the analysis of the technical questions.
In T 900/02 the board stated that a suspicion of partiality inevitably arose if a member of an opposition division, or any other firstinstance body, first solicited and then accepted employment with a firm in which a partner or other employee was conducting a case pending before that member. It stressed that, to be above all suspicion of partiality, every member had to avoid any such situation at any time during the proceedings. No-one could be seen as independent of both parties while in the employ of one of them. The board held that the employment by the respondent's representative's firm of the second examiner was both a fundamental deficiency in the first instance proceedings within the meaning of Art. 10 RPBA and a substantial procedural violation within the meaning of R. 67 EPC 1973.
In T 951/91 (OJ 1995, 202) objections under Art. 24 and Art. 19(2) EPC 1973 were raised by the appellant in the statement of grounds of appeal suggesting that the opposition division had been biased in its attitude to the parties. In reaching its decision on this point, the board observed that nothing in the minutes of the oral proceedings, which the appellant had not criticised, led to the conclusion that the arguments had not been duly considered by the opposition division or that the latter was suspected of bias during those proceedings. The board examined the reasons set out in the appealed decision and observed that the decision itself did not reveal any bias.