Where an application is made to a local planning authority for planning permission, or for any approval of that authority required under a development order, then unless within such period as may be prescribed by the development order, or within such extended period as may at any time be agreed upon in writing between the applicant and the local planning authority, the local planning authority either—
the provisions of section 36 of this Act shall apply in relation to the application as if the permission or approval to which it relates had been refused by the local planning authority, and as if notification of their decision had been received by the applicant at the end of the period prescribed by the development order, or at the end of the said extended period, as the case may be.