(1) Subject to the Tax Acts, where a person carrying on a trade in any chargeable period has incurred capital expenditure on the provision of machinery or plant for the purposes of the trade, an allowance (in this Chapter referred to as a "wear and tear allowance") shall be made to such person for that chargeable period on account of the wear and tear of any of the machinery or plant which belongs to such person and is in use for the purposes of the trade at the end of that chargeable period or its basis period and which, while used for the purposes of the trade, is wholly and exclusively so used.

(2)

(a) Subject to paragraphs (aa), (ab) and (ad) and subsection (4), the amount of the wear and tear allowance to be made shall be an amount equal to -

(i) in the case of machinery or plant, other than machinery or plant of the type referred to in subparagraph (ii), 15 per cent of the actual cost of the machinery or plant, including in that actual cost any expenditure in the nature of capital expenditure on the machinery or plant by means of renewal, improvement or reinstatement, or

(ii) in the case of machinery or plant which consists of a vehicle suitable for the conveyance by road of persons or goods or the haulage by road of other vehicles, 20 per cent of the value of that machinery or plant at the commencement of the chargeable period.