21 Revocation and modification of listed building consent by planning authority.S
(1)If it appears to the planning authority that it is expedient to revoke or modify listed building consent granted on an application made under this Act, the authority may revoke or modify the consent to such extent as they consider expedient.
(2)In performing their functions under subsection (1) the authority shall have regard to the development plan and to any other material considerations.
(3)The power conferred by this section to revoke or modify listed building consent in respect of any works may be exercised at any time before those works have been completed, but the revocation or modification shall not affect so much of those works as has been previously carried out.