(1)Subject to subsection (2) below, the rate at which tax is charged under section 107 above at any time shall be three tenths of the effective rate (that is to say the rate found by expressing the tax chargeable as a percentage of the amount on which it is charged) at which tax would be charged on the value transferred by a chargeable transfer of the description specified in subsection (3) below.
(2)Where the whole or part of the value mentioned in section 107 above is attributable to property which was not relevant property, or was not comprised in the settlement, throughout the period of ten years ending immediately before the ten-year anniversary concerned, the rate at which tax is charged on that value or part shall be reduced by one-fortieth for each of the successive quarters in that period which expired before the property became, or last became, relevant property comprised in the settlement.
(3)The chargeable transfer postulated in subsection (1) above is one—
(a)the value transferred by which is equal to an amount determined in accordance with subsection (4) below ;
(b)which is made immediately before the ten-year anniversary concerned by a transferor who has in the preceding ten years made chargeable transfers having an aggregate value determined in accordance with subsection (5) below; and
(c)for which the appropriate Table of rates is the second Table set out in section 37(3) of the [1975 c. 7.] Finance Act 1975.
(4)The amount referred to in subsection (3)(a) above is equal to the aggregate of—
(a)the value on which tax is charged under section 107 above;
(b)the value immediately after it became comprised in the settlement of any property which was not then relevant property and has not subsequently become relevant property while remaining comprised in the settlement; and
(c)the value, immediately after a related settlement commenced, of the property then comprised in it.
(5)The aggregate value referred to in subsection (3)(b) above is equal to the aggregate of—
(a)the values transferred by any chargeable transfers made by the settlor in the period of ten years ending with the day on which the settlement commenced, disregarding transfers made on that day, and
(b)the amounts on which any charges to tax were imposed under section 108 above in respect of the settlement in the ten years before the anniversary concerned;
but subject to section 110 below.