(1)The Board must under section 20—
(a)compile and maintain the retail prices index, and
(b)publish it every month.
(2)Before making any change to the coverage or the basic calculation of the retail prices index, the Board must consult the Bank of England as to whether the change constitutes a fundamental change in the index which would be materially detrimental to the interests of the holders of relevant index-linked gilt-edged securities.
(3)If the Bank of England considers that the change constitutes a fundamental change in the index which would be materially detrimental to the interests of the holders of relevant index-linked gilt-edged securities, the Board may not make the change without the consent of the Chancellor of the Exchequer.
(4)In this section —
“index-linked gilt-edged securities” means securities issued under section 12 of the National Loans Act 1968 (c. 13) the amount of the payments under which is determined wholly or partly by reference to the retail prices index;
“relevant index-linked gilt-edged securities” means index-linked gilt-edged securities issued before the commencement of this section subject to a prospectus containing provision relating to early redemption in the event of a change to the retail prices index;
“retail prices index” means the United Kingdom General Index of Retail Prices.