111.—(1) Where, in relation to any period, the inspector of taxes, or such other officer as the Revenue Commissioners may authorise to exercise the powers conferred by this section (in this section referred to as “other officer”), has reason to believe that an amount of tax is due and payable to the Revenue Commissioners by a person in any of the following circumstances:

(a) the total amount of tax payable by the person F280[, including tax (if any) payable in accordance] F281[with section 108C(3), 109A(4) or 91J(10)(b)] was greater than the total amount of tax (if any) paid by that person;

(b) the total amount of tax refunded to the person in accordance with section 99(1) was greater than the amount (if any) properly refundable to that person;

(c) an amount of tax is payable by the person and a refund under section 99(1) has been made F282[to the person;]

F283[(d) the total amount of tax refunded to the person in accordance with an order under section 103 was greater than the amount (if any) properly refundable to that person,]

then, without prejudice to any other action which may be taken, the inspector or other officer—

F282[(i) may, in accordance with regulations but subject to section 113, make an assessment in one sum of—

(I) the total amount of tax F280[, including tax (if any) payable in accordance] F281[with section 108C(3), 109A(4) or 91J(10)(b)] which in his or her opinion should have been paid,

(II) the total amount of tax (including a nil amount) which in accordance with section 99(1) should have been refunded, or

(III) the total amount of tax (including a nil amount) which in accordance with the order under section 103 should have been refunded,

as the case may be, in respect of such period, and]

(ii) may serve a notice on the person specifying—

(I) the total amount of tax so assessed,

(II) the total amount of tax (if any) paid by the person or refunded to the person in relation to such period, and

(III) the total amount so due and payable (referred to subsequently in this section as “the amount due”).

F284[(2) Where a notice of assessment is served on a person under subsection (1), the following paragraphs shall apply:

(a) subject to paragraph (b), a person aggrieved by an assessment made on that person under subsection (1) may appeal the assessment to the Appeal Commissioners, in accordance with section 949I of the Taxes Consolidation Act 1997, within the period of 30 days after the date of the notice of assessment;

(b) where, in accordance with section 76 or 77, a person on whom a notice of assessment is served is required to furnish a return and remit the amount of tax payable to the Collector-General, no appeal lies against the assessment until such time as the person—

(i) furnishes the return in respect of each taxable period included in the period referred to in subsection (1), and

(ii) pays or has paid the amount of tax payable on the basis of that return;

(c) in default of an appeal, in accordance with paragraph (a), being made by a person on whom a notice of assessment has been served—

(i) the assessment shall be final and conclusive, and

(ii) the amount due shall be due and payable as if the tax were tax that the person referred to in paragraph (b) is liable to pay for the taxable period during which the period of 14 days after the date of the service of the notice of assessment expires;

and

(d) where an appeal is determined by agreement or otherwise, the amount due as determined in relation to the appeal shall be due and payable as if the tax were tax that the person referred to in paragraph (a) is liable to pay for the taxable period during which the appeal is so determined.

(3) Interest shall not be chargeable in accordance with section 114 from the date on which an assessment is made where—

(a) the amount that was paid in accordance with subsection (2)(b)(ii) is greater than 80 per cent of the amount found to be due on determination of the appeal, and

(b) the balance of the amount found to be due on determination of the appeal is paid within 30 days of such determination.]

F285[(4) An assessment that is otherwise final and conclusive shall not, for any purpose of this Act, be regarded as not final and conclusive or as ceasing to be final and conclusive by reason only of the fact that a Revenue officer has amended, or may amend, the assessment.]