18. Notwithstanding anything contained in any other law for the time being in force, any legal proceeding, whether civil or criminal, which may lawfully be brought against any superior officer or member of the Force for anything done or intended to be done under the powers conferred by, or in pursuance of, any provision of this Ordinance or the rules made thereunder shall be commenced within three months after the act complained of shall have been committed, and not otherwise; and notice in writing of such proceeding and of the cause thereof shall be given to the person concerned and his superior officer at least one month before the commencement of such proceeding.