It is the consistent view of the boards of appeal that in-house knowledge or matter which cannot be identified as forming part of the state of the art within the meaning of Art. 54(2) EPC is irrelevant for substantive patentability (T 1247/06, see also T 654/92, T 1001/98, T 671/08, T 2434/09).

In T 1001/98 the board did not consider it appropriate either for itself or for the examining division to base an assessment of substantive patentability (novelty and inventive step) upon subject‑matter not identified as forming part of the state of the art within the meaning of Art. 54(2) EPC 1973. That was consistent with a number of previous decisions of the boards of appeal (such as T 654/92). In view of the appellant's declaration that the arrangement of figures 7(a) and 7(b) of the patent application was in‑house knowledge not published before the priority date of the patent and given that the European search report did not reveal any corresponding document, the board reached the conclusion that the arrangement concerned could not be treated as being comprised in the state of the art within the meaning of Art. 54(2) EPC 1973 (see also T 1247/06).