if it appears to the local planning authority, having regard to the development plan and to any other material considerations, that it is expedient to revoke or modify any permission to develop land granted on an application made under this Part of this Act, the authority, subject to the following provisions of this section, may by order revoke or modify the permission to such extent as (having regard to those matters) they consider expedient.
Except as provided in section 46 of this Act, an order under this section shall not take effect unless it is confirmed by the Secretary of State; and the Secretary of State may confirm any such order submitted to him either without modification or subject to such modifications as he considers expedient.
Where a local planning authority submit an order to the Secretary of State for his confirmation under this section, the authority shall serve notice on the owner and on the occupier of the land affected and on any other person who in their opinion will be affected by the order; and if within such period as may be specified in that notice (not being less than twenty-eight days from the service thereof) any person on whom the notice is served so requires, the Secretary of State, before confirming the order, shall afford to that person and to the local planning authority an opportunity of appearing before, and being heard by, a person appointed by the Secretary of State for the purpose.