After a copy of a unitary development plan has been sent to the Secretary of State under section 13(2) and before it is adopted by the local planning authority, the Secretary of State may, if it appears to him that the plan is unsatisfactory, direct the authority to modify the proposals in such respects as are indicated in the direction.
An authority to whom a direction is given shall not adopt the plan unless they satisfy the Secretary of State that they have made the modifications necessary to conform with the direction or the direction is withdrawn.