In some decisions, the boards of appeal have held that there has been no tactical abuse and taken late-filed documents into account under the principle of examination by the EPO of its own motion, since these might have put maintenance of the patent at risk (see T 110/89, T 315/92). An abuse of procedure presumes a deliberate withholding of information (see T 534/89). In T 1029/05 the board stated that the issue of admissibility of the late-filed document boiled down to the following questions: (i) whether the late filing is to be seen as an abuse of proceedings, and, if question (i) is answered in the negative, (ii) whether the relevance of the document is prima facie such as to justify its introduction into the proceedings (see also T 2020/09).

In T 1019/92 the board reached the conclusion that the fact that an opponent, after the end of the opposition period, subsequently submitted prior art material originating from itself, did not constitute an abuse of the proceedings in the absence of evidence that this was done deliberately for tactical reasons. The board admitted the late-filed document into the proceedings.

In T 330/88 the board held that the right to be heard (Art. 113(1) EPC 1973) had not been contravened by virtue of a relevant document being submitted late during oral proceedings. The representative was given sufficient time during the oral proceedings held on two consecutive days to consider this document, consisting of only seven pages including the claim page and two figure sheets.

In T 671/03 the opposition division did not admit documents D6 to 16 into the proceedings, stating that they had been filed more than two years after the expiry of the opposition period and were prima facie not so complete as to substantiate the alleged prior use. Three more documents were filed during the appeal proceedings. However, it was not apparent to the board that the submission of documents D6 to D19 had been deliberately delayed for tactical reasons. It therefore held that the late filing was not an abuse of procedure. Documents D6 to D19 could therefore not be disregarded without considering their relevance. Following a detailed examination of the relevance of the various documents, the board concluded that only D18 could be admitted into the proceedings because it was prima facie highly relevant (T 1182/01, T 1029/05).

In T 151/05 the fact that the appellant relied first on prior use 2 and then, after having realised that this argument was not sufficiently substantiated, on other evidence for demonstrating the common general knowledge was seen by the board as a misjudgement but not as an abuse of the proceedings. Consequently, the board considered the relevance of the documents.

In T 1757/06 the opponent (Dow chemical) submitted a patent publication filed by Dow Italia two months before the oral proceedings before the board of appeal. The board held that the opponent and the applicant were separate corporate entities, but nevertheless it would be expected that companies of the same commercial group would have knowledge of their own patent documents. Normally the attempt of a party to file at a late stage one of its own publications will fail, as this is considered to be an abuse of procedure. Although in this case the board did not find that there had been an abuse, it pointed out that the filing at a very late stage of a document that the opponent should have been aware of from the outset of the proceedings could not be condoned.