52.This section replaces section 21 of the 1998 Act and provides for the Board to appoint the Chief Constable and other senior police officers (Assistant Chief Constable and above), subject to the approval of the Secretary of State. Subsection (3) enables the Board to call upon any senior officer to retire in the interests of efficiency and effectiveness with the approval of the Secretary of State. The Secretary of State can require the Board to exercise this power in respect of the Chief Constable.