5 Interception with a warrant.E+W+S+N.I.
(1)Subject to the following provisions of this Chapter, the Secretary of State may issue a warrant authorising or requiring the person to whom it is addressed, by any such conduct as may be described in the warrant, to secure any one or more of the following—
(a)the interception in the course of their transmission by means of a postal service or telecommunication system of the communications described in the warrant;
(b)the making, in accordance with an international mutual assistance agreement, of a request for the provision of such assistance in connection with, or in the form of, an interception of communications as may be so described;
(c)the provision, in accordance with an international mutual assistance agreement, to the competent authorities of a country or territory outside the United Kingdom of any such assistance in connection with, or in the form of, an interception of communications as may be so described;
(d)the disclosure, in such manner as may be so described, of intercepted material obtained by any interception authorised or required by the warrant, and of related communications data.
(2)The Secretary of State shall not issue an interception warrant unless he believes—
(a)that the warrant is necessary on grounds falling within subsection (3); and
(b)that the conduct authorised by the warrant is proportionate to what is sought to be achieved by that conduct.
(3)Subject to the following provisions of this section, a warrant is necessary on grounds falling within this subsection if it is necessary—
(a)in the interests of national security;
(b)for the purpose of preventing or detecting serious crime;
(c)for the purpose of safeguarding the economic well-being of the United Kingdom; or
(d)for the purpose, in circumstances appearing to the Secretary of State to be equivalent to those in which he would issue a warrant by virtue of paragraph (b), of giving effect to the provisions of any international mutual assistance agreement.
(4)The matters to be taken into account in considering whether the requirements of subsection (2) are satisfied in the case of any warrant shall include whether the information which it is thought necessary to obtain under the warrant could reasonably be obtained by other means.
(5)A warrant shall not be considered necessary on the ground falling within subsection (3)(c) unless the information which it is thought necessary to obtain is information relating to the acts or intentions of persons outside the British Islands.
(6)The conduct authorised by an interception warrant shall be taken to include—
(a)all such conduct (including the interception of communications not identified by the warrant) as it is necessary to undertake in order to do what is expressly authorised or required by the warrant;
(b)conduct for obtaining related communications data; and
(c)conduct by any person which is conduct in pursuance of a requirement imposed by or on behalf of the person to whom the warrant is addressed to be provided with assistance with giving effect to the warrant.
Modifications etc. (not altering text)