(1)In the case of any loan relationship represented by an index-linked gilt-edged security, the adjustment for which this section provides shall be made in computing the credits and debits which fall, for any accounting period, to be brought into account for the purposes of this Chapter in respect of that relationship as non-trading credits or non-trading debits.
(2)The adjustment shall be made wherever—
(a)the authorised accounting method applied as respects the index-linked gilt-edged security gives credits or debits by reference to the value of the security at two different times, and
(b)there is any change in the retail prices index between those times.
(3)Subject to subsection (4) below, the adjustment is such an adjustment of the amount which would otherwise be taken for the purposes of that accounting method to be the value of the security at the earlier time (“the opening value”) as results in the amount in fact so taken being equal to the opening value increased or, as the case may be, reduced by the same percentage as the percentage increase or reduction in the retail prices index between the earlier and the later time.
(4)The Treasury may, in relation to any description of index-linked gilt-edged securities, by order provide that—
(a)there are to be no adjustments under this section; or
(b)that an adjustment specified in the order (instead of the adjustment specified in subsection (3) above) is to be the adjustment for which this section provides.
(5)An order under subsection (4) above—
(a)shall not have effect in relation to any gilt-edged security issued before the making of the order; but
(b)may make different provision for different descriptions of securities.
(6)For the purposes of this section the percentage increase or reduction in the retail prices index between any two times shall be determined by reference to the difference between—
(a)that index for the month in which the earlier time falls; and
(b)that index for the month in which the later time falls.
(7)In this section “index-linked gilt-edged securities” means any gilt-edged securities the amounts of the payments under which are determined wholly or partly by reference to the retail prices index.