The Secretary of State may by order made by statutory instrument approve any code of practice issued (whether by him or by another person) for the purpose of—
giving practical guidance to persons engaged in agriculture with respect to activities that may affect controlled waters; and
promoting what appear to him to be desirable practices by such persons for avoiding or minimising the pollution of any such waters,
and may at any time by such an order approve a modification of such a code or withdraw his approval of such a code or modification.
A contravention of a code of practice as for the time being approved under this section shall not of itself give rise to any criminal or civil liability, ...
The Secretary of State shall not make an order under this section unless he has first consulted the river purification authorities.