30Underpayments
(1)Where it has been determined in accordance with the provision made by and by virtue of sections 18 to 21 that a person was entitled, or persons were jointly entitled, to a tax credit for a tax year and either—
(a)the amount of the tax credit paid to him or them for that tax year was less than the amount of the tax credit to which it was so determined that he is entitled or they are jointly entitled, or
(b)no payment of the tax credit was made to him or them for that tax year,
the amount of the difference, or of his entitlement or their joint entitlement, must be paid to him or to whichever of them is prescribed.
(2)Where the claim for the tax credit was made by one person on behalf of another, the payment is to be made to whichever of those persons is prescribed.