Where it appears to the local planning authority that any works have been, or are being, executed to a listed building in .their area and are such as to involve a contravention of section 55(1) or (4) of this Act, then, subject to any directions given by the Secretary of State, they may, if they consider it expedient to do so having regard to the effect of the works on the character of the building as one of special architectural or historic interest, serve a notice—
A notice under this section is in this Act referred to as a " listed building enforcement notice
A listed building enforcement notice shall be served on the owner and on the occupier of the building to which it relates and on any other person having an interest in the building, being an interest which in the opinion of the authority is materially affected by the notice.
Subject to section 97 of this Act, a listed building enforcement notice shall take effect at the end of such period, not being less than twenty-eight days after the service of the notice, as may be specified in the notice.
The local planning authority may withdraw a listed building enforcement notice (without prejudice to their power to serve another) at any time before it takes effect; and if they do so, they shall forthwith give notice of the withdrawal to every person who was served with the notice.