Preliminary
4. Subject to Parts III and IIIA of this Schedule, the amounts to be included in respect of all items shown in a company's accounts shall be determined in accordance with the rules set out in the following paragraphs of this Part.
Fixed Assets
General rules
5. Subject to any provision for depreciation or diminution in value made in accordance with paragraph 6 or 7 of this Schedule the amount to be included in respect of any fixed asset shall be its purchase price or production cost.
6. In the case of any fixed asset which has a limited useful economic life, the amount of -
(a) its purchases price or production cost, or
(b) where it is estimated that any such asset will have a residual value at the end of the period of its useful economic life, its purchase price or production cost less that estimated residual value,
shall be reduced by provisions for depreciation calculated to write off that amount systematically over the period of the asset's useful economic life.