Whether or not the disclosure of the patent in suit is sufficiently clear and complete within the meaning of Art. 100(b) and 83 EPC must be decided by appraising the information contained in the examples as well as other parts of the description in the light of the common general knowledge of the skilled person at the priority date (T 322/93 and T 524/01).

However, where the application disclosed the claimed invention in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art, it then necessarily disclosed at least one way of carrying out the invention disclosed in accordance with R. 42(1)(e) EPC, with the necessary details being derivable from the description including the prior art referred to therein (see e.g. T 389/87, T 561/96 and T 990/07). The board in T 990/07 pointed out that, although the case underlying decision T 561/96 differed from that in T 990/07 in that in T 561/96 the description and the drawings were not erroneous, the board in T 561/96 had also held that in cases where examples were not indispensable, their omission did not contravene R. 27(1)(e) EPC 1973 (R. 42(1)(e) EPC). This Rule only required the insertion of such examples "where appropriate". The jurisprudence of the boards of appeal thus drew a clear distinction between the concepts of "way of carrying out the invention claimed" and "examples" referred to in R. 27(1)(e) EPC 1973. According to this jurisprudence, the detailed description of one way of carrying out the invention claimed had to be interpreted in the light of Art. 83 EPC. It constituted a condition to be met by the description as a whole and was clearly mandatory. In contrast, the presence of examples would only be indispensable if the description would otherwise not be sufficient to meet this requirement. Hence, the purpose of the "examples" evoked in R. 27(1)(e) EPC 1973 appeared primarily to be to complete an otherwise incomplete teaching. See also T 1918/07 and T 1169/08.

In T 226/85 (OJ 1988, 336), T 409/91 (OJ 1994, 653) and T 694/92 (OJ 1997, 408) the patent or the patent application disclosed only one or very few ways of carrying out the invention. In each of these decisions the boards had held that the disclosure of the specific examples was not sufficient to enable the invention to be carried out as claimed. However, according to T 617/07, no principle could be deduced from these decisions that sufficiency of disclosure is always to be denied if there is only example of carrying out an invention. Rather all three decisions emphasised that an objection of lack of sufficiency of disclosure (i) presupposes that there are serious doubts, substantiated by verifiable facts, and (ii) depends on the evidence available in each case whether or not a claimed invention can be considered as enabled on the basis of the disclosure of one worked example.