3(1)At least once in every five years after the date on which a development plan for any area was approved by the Secretary of State, the local planning authority shall carry out a fresh survey of that area, and (subject to paragraph 1 of Schedule 7 to this Act) submit to the Secretary of State a report of the survey, together with proposals for any alterations or additions to the plan which appear to diem to be required having regard thereto.
(2)Without prejudice to the provisions of sub-paragraph (1) of this paragraph, any local planning authority may (subject to paragraph 1 of Schedule 7 to this Act) at any time, and shall if so required by directions of the Secretary of 'State, submit to the Secretary of State proposals for such alterations or additions to the development plan for their area or any part thereof as appear to them to be expedient, or as may be required by those directions, as the case may be.
(3)Where proposals for alterations or additions to a development plan are submitted to the Secretary of State under this paragraph, the Secretary of State may amend that plan to such extent as he considers expedient having regard to those proposals and to any other material considerations.
(4)Where in accordance with the provisions of paragraph 1(5) of this Schedule a development plan has been prepared for part of the area of a local planning authority, and has been approved by the Secretary of State, then (without prejudice to the provisions of sub-paragraph (2) .of this paragraph) the periods of five years mentioned in sub-paragraph (1) of this paragraph shall run from the date on which development plans in respect of the whole of the area have been approved by the Secretary of State.