A gain which accrues on the disposal by any person of—
shall not be a chargeable gain.
In subsection (1) above the reference to the disposal of a contract to acquire or dispose of gilt-edged securities or qualifying corporate bonds is a reference to the disposal of the outstanding obligations under such a contract.
Without prejudice to section 143(5), where a person who has entered into any such contract as is referred to in subsection (1)(b) above closes out that contract by entering into another contract with obligations which are reciprocal to those of the first-mentioned contract, that transaction shall for the purposes of this section constitute the disposal of an asset, namely, his outstanding obligations under the first-mentioned contract.