As acknowledged by the Enlarged Board, the prohibition on double patenting is applicable under Art. 125 (G 4/19). It is a principle of procedural law generally recognised in the contracting states that two patents cannot be granted to the same applicant with claims directed to for the same subject-matter.
The prohibition of double patenting applies to three types of combinations of European applications by the same applicant: two applications filed on the same day, parent and divisional applications, or an application and its priority application.
It is permissible to allow an applicant to proceed with two applications having the same description which do not claim the same subject-matter (see also T 2461/10).In cases where there are two or more European applications from the same applicant designating the same state or states and the claims of those applications have the same filing or priority date and relate to the same invention, the applicant should be required to perform one of the following: amend one or more of the applications in such a manner that the subject-matter of the claims of the applications is not identical, or withdraw overlapping designations, or choose which one of those applications is to proceed to grant. If the applicant does not do so, once one of the applications is granted, the other(s) will be refused under Art. 97(2) in conjunction with Art. 125 (G 4/19). If the claims of those applications are merely partially overlapping, no objection should be raised (see T 877/06). Should two applications of the same effective date be received from two different applicants, each must be allowed to proceed as though the other did not exist.