Making, revocation and amendment of schemes
21.—(1) Subject to paragraph (2), any scheme made under this Part shall be in respect of a year or years and shall be made before the beginning of the first year to which it relates.
(2) Any scheme made under this Part may be amended at any time.
(3) Where an amendment is to be made which relates to a special responsibility allowance payable for the year in which the amendment is made, the scheme shall provide—
(a)that in relation to each of the periods—
(i)beginning with 1st April in that year and ending with the day before that on which the first amendment in that year takes effect; or
(ii)beginning with the day on which an amendment takes effect and ending with the day before that on which the next amendment takes effect, or (if none) 31st March in that year,
the entitlement to such an allowance shall be to payment of such part of the amount of the allowance under the scheme as it has effect during the relevant period as bears to the whole the same proportion as the number of days in the period bears to the number of days in the year; and
(b)that, where a member does not have throughout the whole of any period mentioned in sub-paragraph (a) any such special responsibilities as entitle him to a special responsibility allowance, his entitlement shall be to payment of such part of the allowance referable to each such period (ascertained in accordance with that sub-paragraph) as bears to the whole the same proportion as the number of days in that period during which he has such special responsibilities bears to the number of days in the period.
(4) A scheme made under this Part may be revoked with effect from the beginning of a year and any subsequent year.