Subject to paragraphs 5 and 6, the competent court or authority shall apply national law as to the procedures to be followed in executing such requests and, in particular, as to the appropriate measures of compulsion.
If the court or authority to which the letters rogatory are transmitted is not competent to execute them, the letters rogatory shall be sent forthwith to the central authority referred to in paragraph 1. That authority shall transmit the letters rogatory either to the competent court or authority in that State, or to the European Patent Office where no court or authority is competent in that State.
The execution of letters rogatory shall not give rise to any reimbursement of fees or costs of any nature. Nevertheless, the State in which letters rogatory are executed has the right to require the Organisation to reimburse any fees paid to experts or interpreters and the costs arising from the procedure under paragraph 6.
If the law applied by the competent court or authority obliges the parties to secure evidence and the competent court or authority is not able itself to execute the letters rogatory, that court or authority may, with the consent of the European Patent Office, appoint a suitable person to do so. When seeking such consent, the competent court or authority shall indicate the approximate costs which would result from this procedure. If the European Patent Office gives its consent, the Organisation shall reimburse any costs incurred; otherwise, the Organisation shall not be liable for such costs.
Source: http://www.epo.org/law-practice/legal-texts/html/epc/2016/e/r150.html
Date retrieved: 17 May 2021