If enough electors in an area of a proposed new parish ( ranging from 50 % in an area with less than 500 electors to 10 % in one with more than 2,500 ) sign a petition demanding its creation , then the local district council or unitary authority must consider the proposal . If a sufficient number of electors in an area of a proposed new parish ( ranging from 50 % in an area with less than 500 electors to 10 % in one with more than 2,500 ) sign a petition demanding its creation , then the local district council or unitary authority must consider the proposal .