In this section "directions" means directions given under—
section 94A, or
regulations under section 94C.
Directions are to be given by an instrument in writing.
Directions may be—
general directions applying to all sewerage undertakers, or
directions applying only to one or more sewerage undertakers specified in the directions.
Each sewerage undertaker to whom a direction applies must comply with the direction.
The duties of a sewerage undertaker under this section are enforceable under section 18 by—
the Secretary of State, in the case of directions given by the Secretary of State, and
the Welsh Ministers, in the case of directions given by the Welsh Ministers.