Sch 17 para 5
(1) Where a compliance determination application is made to an authority the authority shall determine whether the works or use in question fail to comply with any planning control which the authority are responsible for enforcing and, if so, shall specify the control in question. (2) Where the authority determine that works or a use fail so to comply they shall further determine whether having regard to all relevant circumstances the works or use shall, notwithstanding the failure, be deemed so to comply, either unconditionally or subject to such conditions as to the time for which the works or use may be continued, the carrying out of alterations, or other matters, as the authority think expedient.