This section applies where—
Sections 72(1)(b) and 73(1)(a) shall not apply to the disposal of the asset or part by the trustee, but any chargeable gain accruing to the trustee on the disposal shall be restricted to the amount of the held-over gain (or a corresponding part of it) on the disposal of the asset to him.
Subsection (2) above shall not have effect in a case within section 73(2) but in such a case the reduction provided for by section 73(2) shall be diminished by an amount equal to the proportion there mentioned of the held-over gain.
In this section "held-over gain" has the same meaning as in section 165 or, as the case may be, 260.