18U.K.Before section 21 (but after the heading “Administration and enforcement”) insert—
“20ACDetermination by Commissioners of composition of substance
(1)The Commissioners may, for any prescribed purpose, determine in such way as they consider appropriate the proportion of any substance that is biodiesel or bioethanol.
(2)In subsection (1) “prescribed purpose” means a purpose, prescribed by regulations made by the Commissioners, that relates to any duty under this Act.”