In T 135/01, the board took the view that the mere observation in the course of an opposition procedure, whether by a party or the opposition division, that the subject-matter of a claim was new having regard to the prior art did not mean that lack of novelty was thereby introduced as a ground for opposition. Thus an assessment of inventive step generally began with a determination of the point of novelty, which implied a finding that the subject-matter of the claim was new. Treating such a routine affirmation of novelty as introducing the opposition ground of lack of novelty would be tantamount to including the latter ground as an invariant concomitant of the opposition ground of lack of inventive step, which would be contrary to decision G 7/95 (OJ 1996, 626 – see in this chapter IV.C.3.4.1).

If a patent has been opposed on the grounds of lack of novelty and lack of inventive step and if only the ground of novelty has been substantiated, a specific substantiation of the ground of lack of inventive step is not necessary. Under such circumstances a specific substantiation of the ground of lack of inventive step is not even generally possible since – given that novelty, i.e. the presence of a difference between the claimed subject-matter and a prior art, is a prerequisite for determining whether an invention involves an inventive step in view of that prior art – this would contradict the reasons in support of lack of novelty. Therefore, the objection of lack of inventive step does not constitute a fresh ground for opposition and can therefore be examined in the appeal proceedings without the agreement of the patentee (T 597/07; see also T 131/01, OJ 2003, 115).

In T 635/06 the notice of opposition specified that the patent in suit was opposed for lack of novelty and lack of inventive step as the respective boxes of the standard EPO form had been crossed and as the notice explicitly indicated both grounds. In the circumstances of the case it was not possible for the opponent to substantiate the ground of lack of inventive step by any analysis going beyond its arguments against novelty. The opponent was thus limited to the position that a comparison of the disclosed composition and the claimed subject-matter revealed no distinguishing feature, the presence of which would, however, be necessary for a detailed objection to inventive step. Hence, the ground of lack of inventive step was considered by the board to be sufficiently addressed and, thus, properly raised in the notice of opposition.

In T 620/08 the opposition was originally based on the ground of lack of inventive step alone but, later in the opposition proceedings, the opponent submitted documents and arguments that the subject-matter of the patent lacked novelty. In its decision, the opposition division set out in detail the reasons why it considered that the subject-matter of the patent was novel over these documents, which then led to its decision not to admit the late-filed ground for opposition. The patentee argued before the board of appeal that, since it had not been admitted into the proceedings by the opposition division, the objection of lack of novelty was a fresh ground for opposition which could not be introduced without the agreement of the patentee. Citing T 986/93 (OJ 1993, 215), the board took the view that the term "fresh ground of opposition" in G 10/91 meant a ground which is relied upon for the first time in appeal proceedings. This, however, was not the case here. Furthermore, a board of appeal was not barred from considering a late-filed ground for opposition which had been disregarded by the opposition division, if it was of the opinion that the opposition division exercised its discretion wrongly in this respect.