This decision deals with the refusal of the Opposition Division (OD) to hear two witnesses on the subject of a prior public use.
[…] In relation to the hearing of witnesses, the Board takes the relevant principles to be:
A party is entitled to adduce evidence by any of the methods set out in A 117. The deciding body cannot choose the evidence which it considers sufficient for establishing the truth: T 474/04 . [2.1]
Nevertheless, it is the function of a witness to confirm what has been alleged (T 543/95) and not to fill in the gaps in facts brought forward to support the case (T 374/02 [1.3, 2nd §]). For this reason, it is necessary that a party who wishes to adduce evidence by means of a witness should indicate what factual details it wishes to prove by this means (T 374/02, [1.3; 1st §]). [2.2]
The credibility (and this includes the reliability) of a witness can only be evaluated by hearing his oral evidence (J 10/04 ). If the maker of a statement is also offered as a witness, it is thus wrong to evaluate his written evidence without hearing him. [2.3]
[…] The sole question on which the OD concentrated in considering the issue of public prior use was whether or not the vehicle which was sold by Eichhoff to Hannover City had a storage reel for a hose. The OD concluded that since documents E8 were insufficient to prove that the hose reel and thus all features of the claim were present, no reason had been seen to hear witnesses. [3.2]
[…] Turning to the OD’s decision not to hear the witnesses, first, as to the offer of Mr Lonke, the Board concludes that the OD was justified in deciding not to hear him. In the notice of opposition he was offered as a witness to prove that the device for the hose-guide depicted in the drawing E8/4 was configured in accordance with the patent, and was delivered on a vehicle to Hannover City. As was pointed out by the OD in its communication of 21 December 2006, however, the drawing E8/4 does not show a reel for winding up a hose and so the evidence offered did not relate to the issue of the hose reel. Although the offer of Mr Lonke as a witness was repeated in the appellant’s letter of 6 February 2007, he was here only offered as witness to confirm what was stated in the letter, which itself only consisted of assertions about what various documents showed, in particular E8/5 and E8/6. The documents, however, spoke for themselves and Mr Lonke’s confirmation of what the documents showed could add nothing relevant to the case. 
As to Mr Fichte, however, the position is different. It is true that the content of his statutory declaration was unsatisfactory. For example, he did not tie the brochure he mentioned to E8/1 or E8/5, he did not state precisely when the lorries he refers to were sold or to whom, nor did he give any details of what was mounted on the vehicles. However, he was also offered as a witness and this was not just to confirm the truth of his declaration. When the letter of 6 February 2007 is read as a whole, including the statement about what the statutory declaration was said to contain, and taken with the other evidence and what was asserted in the notice of opposition, it appears to the Board that he was being offered as a witness to give evidence about the technical details of the lorry which had been sold to Hannover City. One of these technical details concerned the hose reel which was said to be mounted on the vehicle, which was the single point on which the OD expressed itself as not being satisfied about the prior use. 
While the OD was correct in saying that Mr Fichte’s statutory declaration as to facts taking place 20 years previously needed to be considered with care, the OD appears to have overlooked that he was not being offered merely to confirm the contents of the statement. In any event, given that he was being offered as a witness, it was incorrect to evaluate his written evidence without hearing him. 
As to the patentee’s other arguments, it is true that Mr Fichte’s statement was not specific about the details of the vehicle but, again, he was also being offered as a witness to deal with the technical details of the vehicle and there cannot be any real doubt about what it was being said he could deal with in his evidence as a witness, particularly in view of the annotations on E8/6 filed with his statement. The respondent was in a position to know that Mr Fichte might corroborate the fact of the existence of the hose reel if the OD remained in doubt on the basis of the other evidence. The respondent was thus in a position to prepare auxiliary requests to meet this eventuality if the OD had decided to summon Mr Fichte. 
The decision not to hear Mr Fichte was thus wrong and may have affected the outcome of the case, at least as regards the proprietor’s auxiliary request. In the circumstances, the decision as a whole should be set aside and the case remitted to the OD so that the evidence of Mr Fichte can be heard. 
Since the appellant was entitled under the EPC to adduce evidence by any of the methods set out in A 117, the failure to allow it to do so constituted a substantial procedural violation. Since the decision not to hear Mr Fichte may have affected the outcome of the case, it would also be equitable to reimburse the appeal fee. 
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