For the purpose of determining the indexation allowance (if any) on the occasion of a part disposal of an asset, the apportionment under section 42 of the sums which make up the relevant allowable expenditure shall be effected before the application of section 54 and, accordingly, in relation to a part disposal—
On a no gain/no loss disposal by any person ("the transferor")—
and for the purposes of the application of sections 53 and 54 there shall be disregarded so much of any enactment as provides that, on the subsequent disposal of the asset by the person acquiring the asset on the disposal ("the transferee"), the transferor's acquisition of the asset is to be treated as the transferee's acquisition of it.
Where apart from this subsection—
those sums shall be determined as if that subsection had not applied on any such disposal made on or after that date and the loss shall be reduced accordingly or, if those sums are then equal to or less than the consideration for the disposal, the disposal shall be one on which neither a gain nor a loss accrues.
For the purposes of this section a no gain/no loss disposal is one which, by virtue of any enactment other than section 35(4), 53(1) or this section, is treated as a disposal on which neither a gain nor a loss accrues to the person making the disposal.