Paragraph 18

A supply of a taxable commodity is exempt from the levy if the person to whom the supply is made intends to cause the commodity to be used otherwise than as fuel.

The Treasury may by regulations specify, in relation to any commodity, uses of that commodity that, for the purposes of sub-paragraph (1), are to be taken as being, or as not being, uses of that commodity as fuel.

The uses of a commodity that may be specified under sub-paragraph (2) as being uses of that commodity as, or otherwise than as, fuel include uses (“mixed uses”) of the commodity that involve it being used partly as fuel and partly not; but the Treasury must have regard to the object of securing that a mixed use is not specified as being a use of the commodity otherwise than as fuel if it involves the use of the commodity otherwise than as fuel in a way that is merely incidental to its use as fuel.