The final responsibility for establishing whether the application meets the requirement of unity of invention ultimately rests with the Examining Division (see T 631/97, OJ 1/2001, 13; see also VI, 3.2a). For Euro-PCT applications which have entered the European phase, see III, 7.11.

Insofar as it finds that unity of invention is given, if the applicant has paid the further search fee(s) and requested a full or partial refund thereof, the Examining Division will order refund of the relevant further search fee(s).

If the applicant has not availed himself of the opportunity to have the search results on the other inventions included in the search report, he will be taken to have elected that the application should proceed on the basis of the invention which has been searched (see G 2/92, OJ 10/1993, 591). The Examining Division will normally initially uphold the position taken in the search opinion (see B-XII, 1.2) and will then require deletion of all the inventions other than that which has been searched. If the Examining Division is convinced, e.g. by arguments from the applicant, that the opinion on unity at the search stage was incorrect, then an additional search is performed for that part of the subject-matter which is judged to be unitary with an invention which was searched (see B-II, 4.2(iii)) and the examination is carried out on those claims which comply with the requirement of unity of invention.

If the applicant has taken the opportunity to have other inventions searched, then he may determine that the application is to proceed on the basis of any of these, the other(s) being deleted. If the applicant has not yet done so, the examiner should at the beginning of substantive examination, if he maintains the objection of lack of unity, invite the applicant to state on which invention the prosecution of the application should be based and to limit the application accordingly by excising those parts belonging to the other inventions. For the latter inventions, the applicant may file divisional applications (see VI, 9, and A-IV, 1).

Whether or not the question of unity of invention has been raised by the Search Division, it must always be considered by the Examining Division. Whenever unity is found to be lacking, the applicant should be required to limit his claims in such a way as to overcome the objection. Excision or amendment of parts of the description may also be necessary (see II, 7.4). One or more divisional applications, covering matter removed to meet this objection, may be filed (see VI, 9).