Section 307(1) provides that in computing a company’s profits for any period “there should be made” all deductions and additions as are required to give effect to the provisions of the Tax Acts which relate to allowances and charges for capital expenditure. The reference to “shall be made” is not mandatory in relation to allowances but is directive in that it requires the relevant allowances to be made on due claim by the company concerned. Elliss v BP Northern Ireland Refinery Ltd; Elliss v BP Tyne Tanker Co Ltd 1987 STC 52