(1) Subject to the payment of interest in accordance with section 51 and to the provisions of this section, the tax due and payable (other than tax arising by reason of section 20) in respect of a taxable gift or a taxable inheritance may, at the option of the person delivering the return or additional return, be paid by monthly instalments over a period not exceeding 5 years in such manner as may be determined by the Commissioners, the first of which is due on 31 October immediately following the valuation date and the interest on the unpaid tax shall be added to each instalment and shall be paid at the same time as such instalment.

(2) An instalment not due may be paid at any time before it is due.

(3) In any case where and to the extent that the property of which the taxable gift or taxable inheritance consists is sold or compulsorily acquired, all unpaid instalments shall, unless the interest of the donee or successor is a limited interest, be paid on completion of the sale or compulsory acquisition and, if not so paid, shall be tax in arrear.