(1) The Board may, with the approval of the Minister, make a scheme (in this section referred to as a pension scheme) for the provision of pensions or gratuities, or pensions and gratuities, for or in respect of such officers or servants of the Board as it may think fit, and any scheme so made shall be carried out by the Board.

(2) The Board may, with the approval of the Minister, at any time by a subsequent pension scheme (in this subsection and in subsequent subsections of this section referred to as an amending scheme) amend a pension scheme or a previous amending scheme, and any such amending scheme may be expressed to operate retrospectively.

(3) Where an amending scheme amends a pension scheme, an officer or servant to whom such pension scheme applies or applied may, within six months after the coming into operation of the amending scheme, elect not to have the amending scheme apply to him and, if he does so elect, the amending scheme shall not apply to him.

(4) An amending scheme shall not terminate or reduce any pension which was, immediately before the coming into force of such amending scheme, payable under the scheme thereby amended.