46(1)Paragraph 43 material may be retained for as long as a national security determination made by a chief officer of police has effect in relation to it.
(2)A national security determination is made if a chief officer of police determines that it is necessary for any paragraph 43 material to be retained for the purposes of national security.
(3)A national security determination—
(a)must be made in writing,
(b)has effect for a maximum of 5 years beginning with the date on which the determination is made, and
(c)may be renewed.
(4)In this paragraph “chief officer of police” means—
(a)a chief officer of police of a police force in England and Wales,
(b)the chief constable of the Police Service of Scotland, or
(c)the Chief Constable of the Police Service of Northern Ireland.