(1)The ranks that may be held in a police force maintained under section 2 shall include that of assistant chief constable; and in every such police force there shall be at least one person holding that rank.
(2)Appointments and promotions to the rank of assistant chief constable shall be made, in accordance with regulations under section 50, by the police authority after consultation with the chief constable and subject to the approval of the Secretary of State.
(3)Subsections (2), (3) and (4) of section 11 shall apply to an assistant chief constable as they apply to a chief constable.
(4)A chief constable shall, after consulting his police authority, designate a person holding the rank of assistant chief constable to exercise all the powers and duties of the chief constable—
(a)during any absence, incapacity or suspension from duty of the chief constable, or
(b)during any vacancy in the office of chief constable.
(5)No more than one person shall be authorised to act by virtue of a designation under subsection (4) at any one time; and a person so authorised shall not have power to act by virtue of that subsection for a continuous period exceeding three months except with the consent of the Secretary of State.
(6)The provisions of subsection (4) shall be in addition to, and not in substitution for, any other enactment which makes provision for the exercise by any other person of powers conferred on a chief constable.