If the competent department decides of its own motion to obtain an expert opinion (D‑VI, 1, sixth paragraph), it will have to decide in what form it is submitted by the expert whom it appoints. The opinion is drawn up in written form only in cases where the competent department considers that this form is adequate in view of the content of the opinion and provided that the parties agree to this arrangement. As a rule, in addition to submitting a written opinion and introducing it orally, the expert will also be heard (see E‑IV, 1.6).[Rule 121(1); ]

A copy of the opinion must be submitted to the parties. The copy will be produced by the EPO.[Rule 121(3); ]