43.—(1) For the purposes of Schedule 1 to the 1994 Act (annual rates of vehicle excise duty) the cylinder capacity of an internal combustion engine shall be taken to be—
(a)in the case of a single-cylinder engine, the cylinder capacity attributable to the cylinder of the engine; and
(b)in the case of an engine having two or more cylinders, the sum of the cylinder capacities attributable to the separate cylinders.
(2) The cylinder capacity attributable to any cylinder of an internal combustion engine shall be deemed to be equal to—
(a)in the case of a cylinder having a single piston, the product expressed in cubic centimetres of the square of the internal diameter of the cylinder measured in centimetres, and the distance through which the piston associated with the cylinder moves during one half of a revolution of the engine measured in centimetres multiplied by 0.7854; and
(b)in the case of a cylinder having more than one piston, the sum of the products expressed in cubic centimetres of the square of the internal diameter of each part of the cylinder in which a piston moves measured in centimetres, and the distance through which the piston associated with that part of the cylinder moves during one half of a revolution of the engine measured in centimetres multiplied by 0.7854.
(3) In measuring cylinders for the purpose of calculating cylinder capacity, and in calculating cylinder capacity, fractions of centimetres are to be taken into account.