104.—(1) Any earner to whom regulation 103 applies shall, on request, notify his national insurance number to the person who pays him the earnings referred to in that regulation.
(2) The person who pays those earnings shall record on the earner’s deductions working sheet the earner’s national insurance number, and the appropriate category letter as indicated by the Board.
(3) In this regulation “deductions working sheet” has the same meaning as in Schedule 4.