(1)The Director of Savings shall keep a separate account of all sums received or paid with respect to investment deposits.
(2)The said account shall be known as the National Savings Bank Investment Account Fund and is in this Act referred to as " the Investment Account Fund "
(3)The sums to be debited from time to time to the Investment Account Fund shall include—
(a)such sums as the Treasury may determine to be equal to those expended by the Director of Savings in connection with investment deposits;
(b)such sums as the Commissioners and the Treasury may agree to be due to the Commissioners in respect of expenses incurred by them in connection with investment deposits; and
(c)such sums as may be necessary to secure that, year by year, there is contributed to the Exchequers of the United Kingdom and Northern Ireland as nearly as may be what would have been contributed thereto in respect of the National Savings Bank by way of corporation tax if—
(i)the National Savings Bank were a savings bank certified under the [1969 c. 50.] Trustee Savings Banks Act 1969,
(ii)section 339(1) of the [1970 c. 10.] Income and Corporation Taxes Act 1970 (exemption of trustee savings banks from tax in respect of income arising from investments with the Commissioners) had not been enacted, and
(iii)the business of the National Savings Bank were confined to activities concerned with investment deposits.
(4)Sums debited by virtue of paragraph (a) or (c) of subsection (3) above shall be paid into the Consolidated Fund, and those debited by virtue of paragraph (c) shall be treated, for the purposes of subsection (2) of section 22 of the [1920 c. 67.] Government of Ireland Act 1920 (annual determination by Joint Exchequer Board of what part of the proceeds of the reserved taxes is properly attributable to Northern Ireland), as being proceeds of the duties and taxes referred to in subsection (1) of that section.