59.—(1) The deductions allowed in the calculation of self-employed earnings are amounts paid in the assessment period in respect of—
(a)expenses that have been wholly and exclusively incurred for purposes of the trade, profession or vocation, or
(b)in the case of expenses that have been incurred for more than one purpose, an identifiable part or proportion that has been wholly and exclusively incurred for the purposes of the trade, profession or vocation,
excluding any expenses that were incurred unreasonably.
(2) Payments deducted under paragraph (1) may include value added tax.
(3) No deduction may be made for payments in respect of—
(a)expenditure on non-depreciating assets (including property, shares or other assets held for investment purposes);
(b)repayment of capital in relation to a loan taken out for the purposes of the trade, profession or vocation;
(c)expenses for business entertainment.
(4) A deduction for a payment of interest in relation to a loan taken out for the purposes of the trade, profession or vocation may not exceed £41.
(5) This regulation is subject to regulation 60.