(1) In this section -

'qualifying expenditure' means capital expenditure incurred on qualifying machinery or plant by a person carrying on a trade;

'qualifying machinery or plant' means machinery or plant in use in a qualifying premises;

'qualifying premises' has the same meaning as it has in section 843B.

(2) Where a person has incurred qualifying expenditure, and for any chargeable period a wear and tear allowance is to be made under section 284, subsection (2) of that section shall apply as if the reference in paragraph (ad) of that subsection to 12.5 per cent were a reference to 100 per cent.