s 2 Writing-down allowances
(1) Subject to the provisions of this Act, where— (a) any person is, at the end of a chargeable period or its basis period, entitled to an interest in a building or structure, and (b) at the end of the said chargeable period or its basis period, the building or structure is an industrial building or structure, and (c) that interest is the relevant interest in relation to the capital expenditure incurred on the construction of that building or structure, an allowance (in this Chapter referred to as “a writing-down allowance ”’) shall be made to him for the said chargeable period. (2) The writing-down allowance shall be equal to one-twentyfifth (or, where the expenditure was incurred before 6th November 1962, one-fiftieth) of the expenditure mentioned in subsection Capital Allowances Act 1968 Cu. 3 (1)(c) above, except that for a chargeable period of less than a year the said fraction of one-twentyfifth or one-fiftieth shall be proportionately reduced. (3) Where the interest in a building or structure which is the relevant interest in relation to any expenditure is sold while the building or structure is an industrial building or structure, then (subject to any further adjustment under this subsection on a later sale) the writing-down allowance for any chargeable period, if that chargeable period or its basis period ends after the time of the sale, shall be the residue (as defined in section 4(1) of this Act) of that expenditure immediately after the sale, reduced in the proportion (if it is less than one) which the length of the chargeable period bears to the part unexpired at the date of the sale of the period of twenty-five years (or, where the expenditure was incurred before 6th November 1962, fifty years) beginning with the time when the building or structure was first used. (4) Notwithstanding anything in the preceding provisions of this section, in no case shall the amount of a writing-down allowance made to a person for any chargeable period in respect of any expenditure exceed what, apart from the writing off falling to be made by reason of the making of that allowance, would be the residue of that expenditure at the end of that chargeable period or its basis period.