If before the expiration of the said period of three months an objection is received by the Minister from any council, authority or board on whom a copy of the notice is required to be served under paragraph 2 of this Schedule, or from any other person affected by the proposed scheme, and the objection is not withdrawn, the Minister shall cause a local inquiry to be held :

Provided that except where the objection is made by any such council, authority or board as aforesaid, the Minister may dispense with such an inquiry if he is satisfied that in the circumstances of the case the holding of such an inquiry is unnecessary.