(1) Except in the cases mentioned in this section, any allowance or charge made to or on a person under the preceding provisions of this Part shall be made to or on such person in taxing such person's trade or, as the case may require, in charging such person's income under Case V of Schedule D.
(2) An industrial building allowance shall be made to a person by discharge or repayment of tax if such person's interest in the building or structure is subject to any lease when the expenditure is incurred or becomes subject to any lease before the building or structure is first used for any purpose; but this subsection shall not apply as respects income chargeable under Case V of Schedule D.
(3) A writing-down allowance shall be made to a person for a chargeable period by means of discharge or repayment of tax if such person's interest is subject to any lease at the end of that chargeable period or its basis period; but this subsection shall not apply as respects income chargeable under Case
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