http://www.legislation.gov.uk/id/ukpga/2004/20

Part 1The Civil Nuclear Industry

The Police Authority—

must appoint a chief constable of the Constabulary and a deputy chief constable of the Constabulary; and

may appoint one or more assistant chief constables of the Constabulary.

Before appointing the deputy chief constable or an assistant chief constable, the Police Authority must consult the chief constable.

The chief constable, the deputy chief constable and every assistant chief constable are to be members of the Constabulary.

The approval of the Secretary of State is required for the making of an appointment under this section.

Schedule 11 (which makes provision about the removal and suspension of the chief constable and other senior officers) has effect.