471 Determination of entitlement or liabilityU.K.
(1)Whether a person is entitled to a writing-down allowance or a balancing allowance, or liable to a balancing charge, for a chargeable period is determined separately for each pool of qualifying expenditure and depends on—
(a)the available qualifying expenditure in that pool for that period (“AQE”), and
(b)the total of any disposal receipts to be brought into account in that pool for that period (“TDR”).
(2)If AQE exceeds TDR, the person is entitled to a writing-down allowance or a balancing allowance for the period.
(3)If TDR exceeds AQE, the person is liable to a balancing charge for the period.
(4)The entitlement under subsection (2) is to a writing-down allowance except for the final chargeable period when it is to a balancing allowance.
(5)The final chargeable period for a pool to which qualifying trade expenditure has been allocated is the chargeable period in which the trade is permanently discontinued.
(6)The final chargeable period for a pool to which qualifying non-trade expenditure has been allocated is the chargeable period in which the last of the patent rights on which the person has incurred qualifying non-trade expenditure—
(a)comes to an end without any of those rights being revived, or
(b)is wholly disposed of.