Health and Safety at Work etc. Act 1974

3(1)If a member becomes or ceases to be the chairman or deputy chairman, the Secretary of State may vary the terms of the instrument appointing him to be a member so as to alter the date on which he is to vacate office as a member.

(2)If the chairman or deputy chairman ceases to be a member he shall cease to be chairman or deputy chairman, as the case may be.