2.7.4 Hearing witnesses

For relevance of the evidence see chapter III.G.3.1. "Relevance of the evidence" and for further aspects of the right to be heard while taking evidence see chapter III.G.3.3. "Right to be heard".

In T 142/97 the board held that the opposition division had violated the opponent's right to be heard under Art. 113(1) EPC by not hearing the witness offered in connection with a prior use that had been adequately substantiated in the notice of opposition. See also T 959/00 in which the board held that the opposition division's failure to hear the witness, and the absence in the decision under appeal of any reference to a reason why it had not been necessary to hear the witness, amounted to a fundamental procedural violation of the right to be heard.

In T 269/00 the board held that the case before it differed from T 142/97 because the ground of prior use was not adequately substantiated during the opposition period, but completed piecemeal during the opposition proceedings. The board concluded that not hearing the witness did not amount to a substantial procedural violation.

In T 474/04 (OJ 2006, 129), the board held that if assertions made in an unsworn witness declaration remained contested, a request to hear the witness had to be granted before these assertions were made the basis of a decision against the contesting party.

In T 909/03 the hearing of a witness took place in the morning and the oral proceedings continued in the afternoon. The board held that it was not necessary for a party to be given a copy of the minuted testimony before commenting on that testimony. During the oral proceedings the party had been given sufficient opportunity to comment. No substantial procedural violation had thus occurred.

In T 716/06 the board confirmed that where oral evidence of a witness was requested by a party the competent department should grant this request only if it considered this oral evidence necessary to clarify matters that were decisive for the decision to be taken. However, where an opponent requested that a witness be heard on an alleged public prior use and on the disclosure of a certain feature by this prior use, the competent department as a rule had to grant this request before deciding that the alleged public prior use was neither established nor constituted a novelty-destroying state of the art.

In T 1100/07 the board held that the opposition division should have heard one of the offered witnesses. Since the opposition division had based its final decision on a failure to establish the prior existence of a single given feature and the witness would allegedly have been able to give evidence on that very point, the refusal to hear him was wrong and might have affected the outcome of the decision. The appellant was entitled under the EPC to adduce evidence by any of the methods set out in Art. 117 EPC and thus failure to allow it to do so constituted a substantial procedural violation. See also T 2386/19 and T 2517/22. Moreover, according to the board in T 2517/22, it is an opposition division's duty to take its decision on the basis of all the relevant evidence actually available rather than to expect the presentation of more preferred pieces of documentary evidence, to speculate on the reasons of and draw conclusion from their absence (see also chapter III.G.3.3.4 "Improper reasons for rejection of evidence offered").

In T 1738/21 the board held that the opposition division’s failure to hear three of the offered witnesses amounted to a "serious procedural violation". According to the board it appeared that the witness testimonies had been relevant for the features which had been decisive for the decision in the opposition proceedings. The board could not find any mention in the decision under appeal of the appellant’s offer of witnesses nor any indication of the opposition division’s reasons for not hearing the witnesses offered. The board recalled that Art. 117(1) and 113(1) EPC embody a basic procedural right, namely that a party can give evidence in an appropriate form and have that evidence heard. If the evidence offered related to alleged facts that were decisive to the decision to be taken, the department hearing the case had, as a rule, to order it to be taken.

In T 423/22 the board emphasised that hearing the witness by videoconference in the case in hand had not infringed the appellant's right to be heard because it had not substantially limited the interaction between the opposition division, the parties and the witness compared to hearing a witness in the courtroom. Even if part of the body language could not be seen, this drawback could never affect a party's right to be present and to put questions to the witness to such an extent that its right to be heard, i.e. the "opportunity to present comments on grounds or evidence" (Art. 113(1) EPC), would be violated. For more information on this decision see also chapters III.C.8.3.3e) "Applicability of considerations set out in G 1/21 date: 2021-07-16 to first-instance proceedings and to hearing a witness" and III.G.3.1.8 "Means of taking evidence by videoconference".