6Where before 1st April 1986 the Secretary of State directed that any local plan or proposals for the alteration, repeal or replacement of a local plan which had been prepared by a metropolitan county council before 1st April 1986 but had not been adopted or approved should not have effect unless approved by him, he shall continue to consider the plan or the proposals and give his decision on them as if the plan or proposals had been prepared and submitted by the metropolitan district council whose area is affected by the plan or proposals or, where the areas of two or more such councils are affected, as if the plan or proposals had been a joint plan or joint proposals prepared by those councils.