This section applies if a return is amended under section 9ZA of this Act (amendment of personal or trustee return by taxpayer), or in accordance with Chapter 2 of Part 4 of the Finance Act 2014 (amendment of return after follower notice), at a time when an enquiry into the return is in progress in relation to any matter to which the amendment relates or which is affected by the amendment.
The amendment does not restrict the scope of the enquiry but may be taken into account (together with any matters arising) in the enquiry.
So far as the amendment affects the amount stated in the self-assessment included in the return as the amount of tax payable, it does not take effect while the enquiry is in progress in relation to any matter to which the amendment relates or which is affected by the amendment and—
(a) if the officer states in a partial or final closure notice that he has taken the amendment into account and that—
(i) the amendment has been taken into account in formulating the amendments contained in the notice, or
(ii) his conclusion is that the amendment is incorrect,
the amendment shall not take effect;
(b) otherwise, the amendment takes effect when a partial closure notice is issued in relation to the matters to which the amendment relates or which are affected by the amendment or, if no such notice is issued, a final closure notice is issued.
For the purposes of this section the period during which an enquiry is in progress in relation to any matter is the whole of the period—
(a) beginning with the day on which notice of enquiry is given, and
(b) ending with the day on which a partial closure notice is issued in relation to the matter or, if no such notice is issued, a final closure notice is issued.