3.1.2 Offering evidence – effect on the outcome of the dispute – refusal to hear a witness

See the introduction above with reference to T 329/02, T 860/01, and T 474/04 (OJ 2006, 129).

The reported cases primarily concern witness testimonies. However, reference is also made to other forms of evidence offered such as visual inspection.

According to T 716/06, it is true that where oral evidence of a witness is requested by a party the competent EPO department should grant this request only if it considers this oral evidence necessary, i.e. when it is required to clarify matters that are decisive for the decision to be taken. If a request is made by an opponent to hear a witness on an alleged public prior use and on the disclosure of a certain feature by this prior use, the competent department of the EPO must as a rule grant this request before deciding that the alleged public prior use is neither established nor a novelty-destroying part of the state of the art because the feature in question is not found to be disclosed therein. In T 2003/08 of 31 October 2012 date: 2012-10-31 the board – in contrast to the opposition division – considered it appropriate to hear the witnesses because their testimony could affect the outcome of the proceedings.

In T 246/17 the opposition division had declined to hear the witnesses offered in relation to prior use and considered the public prior use to be adequately proven by the documentary evidence. However, the board came to the conclusion that it could not be ruled out that hearing the witnesses, alongside evaluating the documentary evidence, could have led to a different assessment of novelty and inventive step and thus to a different outcome. The disclosures of documents O1 (manual) and O2 (brochure) left open whether certain features were present in the instrument described, but the instrument had actually been made and sold and might itself have disclosed them even though O1 and O2 did not, and this was a matter which witness testimony could resolve. Not hearing the witnesses was therefore a fundamental procedural violation that justified setting the decision aside (see e.g. T 716/06, T 1363/14 and T 314/18, and for a more recent, very detailed example on this topic, T 1738/21, summarised below in this chapter III.G.3.3.4).

In T 1100/07 (alleged prior use, sale of a vehicle with a given feature) the department of first instance had refused to hear two witnesses. The board held that it had been right to refuse to hear one of them, as he would merely have confirmed what he had said in his written statement about documents that anyway spoke for themselves and hearing him would have had no impact on the final decision. It should, however, have heard the other witness. It was true that the request that he be heard had been filed late and that granting it would have meant adjourning the oral proceedings, but 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. Thus, the refusal to hear him was wrong and might have affected the outcome of the decision.

In T 273/16 during the opposition proceedings the appellant-opponent had, on multiple occasions, requested that two witnesses be heard on the alleged prior use of a commercial dishwasher. The opposition division had opted not to invite the witnesses. Its decision appeared to be based primarily on the fact that no production or sale of the dishwasher had been demonstrated. Yet the opponent had offered the two witnesses in relation to that very issue. The decision not to hear the witnesses was therefore incorrect and might have influenced the outcome of the proceedings.

In T 2386/19 the opposition division of its own motion cast doubts for the first time at oral proceedings on whether or not feature M6 was disclosed by the prior use. The appellant/opponent reacted by requesting to hear a witness to corroborate an alleged fact which was relevant. The opposition division did not grant the request for the hearing of a witness even though it had been made at the first available opportunity and the opposition division had considered the outcome of the hearing to be relevant to the outcome of the case. The board decided that the refusal to hear the witness violated the appellant/opponent's right to be heard under Art. 113(1) EPC and might have affected the outcome of the appealed decision.

In T 778/21 (laundry appliance), concerning the general principles for assessing an alleged prior use, the board set out four steps that should generally be made (set out in detail in the Reasons). Steps 1 to 3 comprised the examination of the substantiation of the prior use, establishing the evidence offered by the opponent as bearing the burden of proof and the evaluation of the entire evidence offered by the opponent. Depending on the outcome of this evaluation, step 4 could entail one of three variants, depending on whether or not the opponent's evidence on file confirmed the alleged facts, or if doubts remained, and whether the opponent did (first variant) or did not (second variant) request an inspection or hearing of witnesses (see the detailed Reasons as to the consequences). If, in the third variant, the opponent's evidence confirmed the prior use, the (counter) evidence offered by the patent proprietor would become relevant and would need to be considered. If assertions made in an affidavit or in any other witness declaration remained contested, a request from a party to hear the (available) witness would have to be granted. The board made reference to G 2/21 (points 41, 42, 44 of the Reasons) and to T 474/04. In T 778/21 the board applied these general principles for assessing the alleged prior use. Steps 1 to 3 of the assessment were fulfilled. Step 4 concerned the third variant, therefore the proprietor's request for an inspection of the washing machine and for hearing the authors of the affidavits as witnesses needed to be granted. Based on the submissions and evidence on file, the board found that the opponent had substantiated that the machine of the prior use had been made available to the public and had provided evidence confirming the related facts. Based on the evidence on file, all features of claim 1 were seen to be known from the prior use. Therefore, the patent proprietor's request for taking (counter) evidence (step 4, third variant) needed to be considered. A final conclusion on whether all relevant aspects of the prior use, including public availability, were proven beyond reasonable doubt, could only be drawn after considering the evidence requested to be considered by the proprietor, i.e. after inspecting the machine and hearing the witnesses. The case was remitted to first instance for further prosecution.