The council shall exercise its power to appoint political members of a sub-group so as to ensure that, so far as practicable, the political members of all the sub-groups, taken together, reflect the balance of parties prevailing among the members of the council immediately after the last local general election.

Subject to the following provisions of this paragraph, a person shall hold and vacate office as a political member in accordance with the terms of his appointment.

A political member shall hold office until the date of the local general election next following his appointment.

A person appointed to fill a casual vacancy shall hold office for the remainder of the term of the political member in whose place he is appointed.

A person whose term of office as a political member expires or who has resigned shall be eligible for re-appointment.

Where a political member ceases to hold office at any time during the transitional period, no appointment shall be made to fill the casual vacancy; and paragraph 2 and sub-paragraph (1) of this paragraph shall have effect subject to this sub-paragraph.