Under regulations promulgated by the Council of the District of Columbia, each officer and member of the Metropolitan Police force and of the Fire Department of the District of Columbia, when he may be required to work on any holiday, shall be compensated for such duty, excluding periods when he is in a leave status, in lieu of his regular rate of basic compensation for such work, at the rate of twice such regular rate of basic compensation; provided, that for the purpose of this subchapter, each such officer or member who works 8 hours or less on any holiday shall be compensated for such duty in addition to his regular rate of basic compensation for such work, at the rate of one eighth of his daily rate of basic compensation for each hour so worked, computed to the nearest hour, counting 30 minutes or more as a full hour; provided further, that, when an officer or member is authorized or directed to work on a holiday and such officer or member is required to work longer than his regular tour of duty, he shall be compensated for such overtime in accordance with the provisions of subsection (e) of § 5-1304. Appropriations for personal services for the Metropolitan Police force, the Fire Department of the District of Columbia, and the United States Park Police Force shall be available for payment of the additional compensation authorized by this subchapter.