A document considered during the examination procedure is not automatically scrutinised in opposition or opposition appeal proceedings, even if it is quoted and acknowledged in the contested European patent (T 155/87, T 198/88, OJ 1991, 254; T 484/89, T 652/99). Generally, it has to be relied upon by a party to be considered by the opposition division.

According to T 291/89 this also applied to a document cited in the search report. In T 111/04 the board agreed with the case law and considered that this applied also to evidence filed during the grant proceedings.

In T 536/88 (OJ 1992, 638) the board pointed out, however, that the document cited and acknowledged in the description of the contested patent itself as the closest prior art and on the basis of which the technical problem in the description was formulated remains an exception. Such a document also forms part of the opposition or opposition appeal proceedings even if it is not expressly cited within the opposition period (T 541/98, T 652/99, T 454/02, T 86/03).

In T 140/00 although document (7) had been cited in the specification of the patent in suit, it had merely been acknowledged as conventional background art; it was not considered therein as essential or as the closest prior art and starting point of the claimed invention. Therefore, that document did not automatically form part of the appeal proceedings and, thus, was late-filed evidence subject to a discretionary decision of the board.

In T 234/90, T 300/90 and T 501/94 (OJ 1997, 193) the board held that a document indicated in a citation as the closest prior art for the purpose of elucidating the technical problem set out in the citation did not automatically form part of the opposition or opposition appeal proceedings.

In the board's view in T 387/89 (OJ 1992, 583), neither an opposition division nor a board of appeal had any duty to reconsider the relevance of documents cited in the European search report if such documents had not been relied upon by the opponents to support their grounds of opposition. Under Art. 114(1) EPC 1973, however, an opposition division or appeal board could introduce new documents into the opposition proceedings if it had good reason to suppose that the documents could affect the outcome of the decision (T 420/93, T 530/00).