(1) The succeeding provisions of this regulation have effect in respect of contributions under regulation 18.
(2) The contributor shall, subject to subregulation (3), be liable to pay the contributions in respect of each unit of pension until immediately after the last fortnightly payment before he ceases to be an employee.
(3) In the case of a contributor whose initial payment in respect of the contributions in respect of a unit of pension is made within twelve months before, or at any time after, he attains the maximum age for retirement, he shall pay those contributions until he ceases to be an employee by reason of his death or retirement on the ground of invalidity or physical or mental incapacity to perform his duties, or until he has paid twenty - six contributions, whichever first happens.