(1)Where the conditions mentioned in subsection (2) below are not satisfied in relation to any interest to which the claim relates then, subject to subsections (3) and (4) below, an addition shall be made to the sale price of the interest; and the amount of the addition shall be equal to the difference between—
(a)the value on death of the interest, and
(b)what that value would have been if the circumstances prevailing at the date of the sale and by reason of which the conditions are not satisfied had prevailed immediately before the death.
(2)The conditions referred to in subsection (1) above are—
(a)that the interest was the same in all respects and with the same incidents at the date of the death and at the date of the sale; and
(b)that the land in which the interest subsists was in the same state and with the same incidents at the date of the death and at the date of the sale.
(3)If after the date of the death but before the date of the sale compensation becomes payable under any enactment to the appropriate person or any other person liable for tax attributable to the value of the interest—
(a)because of the imposition of a restriction on the use or development of the land in which the interest subsists, or
(b)because the value of the interest is reduced for any other reason,
the imposition of the restriction or the other cause of the reduction in value shall be ignored for the purposes of subsections (1) and (2) above, but there shall be added to the sale price of the interest an amount equal to the amount of compensation.
(4)Where the value on death of an interest is less than it would have been as mentioned in subsection (1) above, that subsection shall apply as if, instead of providing for an addition to be made to the sale price, it provided for that price to be reduced to what it would have been if the change in circumstances by reason of which the conditions mentioned in subsection (2) above are not satisfied had not occurred.