Finance Act 2009

16 (1) Where—

(a) income tax or capital gains tax has been paid for a chargeable period (“period A”), and

(b) relief from any amount of that tax is given to a person (“P”) by repayment,

P is entitled to require that the amount repaid be treated for the purposes of paragraph 15(3), so far as it will go, as if it were a discharge of a qualifying charge to tax.

(2) A qualifying charge to tax is any amount of tax charged on P (whether alone or together with other persons) by or by virtue of any assessment for or relating to period A.

(3) But sub-paragraph (1) does not permit an amount to be applied—

(a) to any assessment made after the relief was given, or

(b) to more than one assessment so as to reduce, without extinguishing, the amount of tax charged.