(1) Tax shall be due and payable on the valuation date.

(1A)

(a) Simple interest is payable, without deduction of income tax, on the tax arising by reason of section 15(1) or 20(1) from the valuation date to the date of payment of that tax, and the amount of that interest shall be determined in accordance with paragraph (c) of subsection (2).

(b) Interest payable in accordance with paragraph (a) is chargeable and recoverable in the same manner as if it were part of the tax.

(2)

(a) Simple interest is payable, without deduction of income tax, on the tax where the relevant date (within the meaning of section 46(5)) occurs -