51.—(1) Where all or part of a pension or lump sum payment due under these Regulations, the Benefits Regulations or the Earlier Regulations is not paid within the relevant period after the due date, the appropriate administering authority must pay interest on the unpaid amount to the person to whom it is payable (see regulation 44(4)).
(2) The relevant period is—
(a)in the case of a pension under regulation 24(1), 27(1), 33(1) or 36(1) of the Benefits Regulations, the period ending one month after the date on which the administering authority receives notification of the member’s death;
(b)in the case of any other pension, one year;
(c)otherwise, one month.
(3) The due date is—
(a)in the case of a pension, the date on which it becomes payable;
(b)in the case of a lump sum under the Transitional Regulations or regulation 21 of the Benefits Regulations (election for lump sum in lieu of pension), the benefit crystallisation date;
(c)in the case of a death grant under regulation 23, 32 or 35 of the Benefits Regulations, the date on which the member dies or, where notification of death is received more than two years after the date of death, the date of notification; and
(d)in the case of a payment of a lump sum under regulation 39 (commutation: small pensions) of the Benefits Regulations, the date of the commutation election or, if later, the nominated date (within the meaning of paragraph 7(3) of Part 1 of Schedule 29 to the Finance Act 2004).