R. 137(5) EPC states: "Amended claims may not relate to unsearched subject-matter which does not combine with the originally claimed invention or group of inventions to form a single general inventive concept. Nor may they relate to subject-matter not searched in accordance with Rule 62a or Rule 63".

According to well-established case law, R. 137(5) EPC does not apply when the applicant has not paid the search fee in respect of a non-unitary invention relating to the originally filed claims (see T 708/00, OJ 2004, 160; T 1285/11).

In T 613/99 the board stated that R. 86(4) EPC 1973 referred to a particular situation, i.e. where subject-matter was described but not claimed in the original application and was therefore not searched; where that subject-matter failed to meet the requirement for unity of invention with the matter claimed in the application; and where, following the search report, the applicants had filed fresh claims relating only to this unsearched matter. In this situation, the patentability of these fresh claims could not be examined in the context of the original application, since this would have amounted to a derogation from the principle endorsed in G 2/92 (OJ 1993, 591), according to which the invention to be examined had to be an invention for which a search fee had been paid. In the case in hand, the situation was entirely different. The claimed subject-matter in the application at issue had been claimed in the original application and had therefore been searched, even if it had not been possible to carry out a meaningful search. Moreover, the invention forming the subject of claims 1 and 2 of the application at issue was substantially the same as that which formed the subject of claims 1 and 2 of the original application. In such a situation, if the examining division rejected a finding of the search division regarding matter excluded from the search, a so-called additional European search could be carried out at the request of the examining division.