This section applies if (apart from this section) the trustees incur an allowable expense in a tax year prior to the current tax year (“the earlier tax year”).

For the purposes of this Chapter the trustees are treated as having incurred the allowable expense in the current tax year so far as conditions A and B are met in relation to the expense.

Condition A is that the allowable expense could not be set against the trustees' trust rate income for the earlier tax year only because the trustees' trust rate income was insufficient or they had no trust rate income.

Condition B is that the allowable expense has not been set against the trustees' trust rate income for a tax year prior to the current tax year as a result of this section.