The Lord Mayor for the time being, if not disqualified, shall be chairman of the justices, with the style of Chief Magistrate, instead of a chairman being elected under section 17(1) of this Act; and, subject to subsection (3) below, the aldermen who have been Lord Mayor and are not disqualified (or, if there are more than eight such aldermen, the eight who were last Lord Mayor) shall be deputy chairmen in addition to any deputy chairmen elected under section 17(1) above.

For the purposes of this section a Lord Mayor or alderman is disqualified at any time while his name is entered in the supplemental list.

In the event of a Lord Mayor being disqualified, then during his mayoralty the senior of the aldermen designated as deputy chairmen in subsection (1) above shall, instead of being a deputy chairman, be chairman of the justices as acting Chief Magistrate.

Subsections (2) and (3) of section 17 of this Act shall apply to any Lord Mayor or alderman as chairman or deputy chairman of the justices as they apply to a chairman or deputy chairman elected under subsection (1) of that section.