(1)So far as directed to do so by the Prime Minister and subject to subsection (2), the Investigatory Powers Commissioner must keep under review the carrying out of any aspect of the functions of—
(a)an intelligence service,
(b)a head of an intelligence service, or
(c)any part of Her Majesty’s forces, or of the Ministry of Defence, so far as engaging in intelligence activities.
(2)Subsection (1) does not apply in relation to anything which is required to be kept under review by the Investigatory Powers Commissioner under section 229.
(3)The Prime Minister may give a direction under this section at the request of the Investigatory Powers Commissioner or the Intelligence and Security Committee of Parliament or otherwise.
(4)The Prime Minister must publish, in a manner which the Prime Minister considers appropriate, any direction under this section (and any revocation of such a direction) except so far as it appears to the Prime Minister that such publication would be contrary to the public interest or prejudicial to—
(a)national security,
(b)the prevention or detection of serious crime,
(c)the economic well-being of the United Kingdom, or
(d)the continued discharge of the functions of any public authority whose activities include activities that are subject to review by the Investigatory Powers Commissioner.