If the Secretary of State is satisfied that a member of a residual body—
(a) has been absent from meetings of the body of which he is a member for a period longer than six consecutive months without the permission of that body;
(b) has become bankrupt or made an arrangement with his creditors;
(c) is incapacitated by physical or mental illness; or
(d) is otherwise unable or unfit to discharge the functions of a member,
the Secretary of State may declare his office as a member to be vacant; and thereupon the office shall become vacant.