(1)This section applies if—
(a)a person is entitled to an allowance for income tax purposes,
(b)that person enters into a tax agreement with the Inland Revenue for the tax year in which the allowance would be given effect, and
(c)no assessment giving effect to the allowance is made for that tax year.
(2)In this section “tax agreement” means an agreement in writing as to the extent to which the allowance in question is to be given effect for the tax year in question.
(3)If this section applies, the allowance is to be treated as if it had been given effect under an assessment—
(a)for the tax year for which the tax agreement is made, and
(b)to the extent set out in the tax agreement.
(4)A tax agreement may relate to any method by which allowances are given effect under this Act.