Where any amount of interest is payable under section 86 ... of this Act in relation to an assessment, and relief from tax charged by the assessment is given to any person by a discharge of any of that tax, such adjustment shall be made of the said amount, and such repayment shall be made of any amounts previously paid under that section in relation to the assessment, as are necessary to secure that the total sum, if any, paid or payable under that section in relation to the assessment is the same as it would have been if the tax discharged had never been charged.
Where interest is payable under section 87A of this Act in respect of an amount of corporation tax for an accounting period, and relief from tax is given by a discharge of any of that corporation tax—
as are necessary to secure that the total sum (if any) paid or payable under that section in respect of corporation tax for that accounting period is the same as it would have been if the tax discharged had never been charged.
Subsection (1A) above has effect subject to section 87A(4), (4A), (4B), (6) and (7) of this Act.
Subject to subsection (2A) below Where relief from tax ... paid for any chargeable period is given to any person by repayment, he shall be entitled to require that the amount repaid shall be treated for the purposes of this section, so far as it will go, as if it were a discharge of the tax charged on him (whether alone or together with other persons) by or by virtue of any assessment for or relating to the same chargeable period, so, however, that it shall not be applied to any assessment made after the relief was given and that it shall not be applied to more than one assessment so as to reduce, without extinguishing, the amount of tax charged thereby.
In any case where—
that person shall be entitled to require that the amount repaid shall be treated for the purposes of this section, so far as it will go, as if it were a discharge of the corporation tax charged on him for that period.
Notwithstanding anything in the preceding provisions of this section, no relief, whether given by way of discharge or repayment, shall be treated for the purposes of this section as—
For the purposes of this section a relief from corporation tax or capital gains tax shall not be treated as affecting tax charged by any assessment unless the assessment is to the same tax .