15General safeguards
(1)Subject to subsection (6), it shall be the duty of the Secretary of State to ensure, in relation to all interception warrants, that such arrangements are in force as he considers necessary for securing—
(a)that the requirements of subsections (2) and (3) are satisfied in relation to the intercepted material and any related communications data; and
(b)in the case of warrants in relation to which there are section 8(4) certificates, that the requirements of section 16 are also satisfied.
(2)The requirements of this subsection are satisfied in relation to the intercepted material and any related communications data if each of the following—
(a)the number of persons to whom any of the material or data is disclosed or otherwise made available,
(b)the extent to which any of the material or data is disclosed or otherwise made available,
(c)the extent to which any of the material or data is copied, and
(d)the number of copies that are made,
is limited to the minimum that is necessary for the authorised purposes.
(3)The requirements of this subsection are satisfied in relation to the intercepted material and any related communications data if each copy made of any of the material or data (if not destroyed earlier) is destroyed as soon as there are no longer any grounds for retaining it as necessary for any of the authorised purposes.
(4)For the purposes of this section something is necessary for the authorised purposes if, and only if—
(a)it continues to be, or is likely to become, necessary as mentioned in section 5(3);
(b)it is necessary for facilitating the carrying out of any of the functions under this Chapter of the Secretary of State;
(c)it is necessary for facilitating the carrying out of any functions in relation to this Part of the Interception of Communications Commissioner or of the Tribunal;
(d)it is necessary to ensure that a person conducting a criminal prosecution has the information he needs to determine what is required of him by his duty to secure the fairness of the prosecution; or
(e)it is necessary for the performance of any duty imposed on any person by the [1958 c. 51.] Public Records Act 1958 or the [1923 c. 20 (N.I.).] Public Records Act (Northern Ireland) 1923.
(5)The arrangements for the time being in force under this section for securing that the requirements of subsection (2) are satisfied in relation to the intercepted material or any related communications data must include such arrangements as the Secretary of State considers necessary for securing that every copy of the material or data that is made is stored, for so long as it is retained, in a secure manner.
(6)Arrangements in relation to interception warrants which are made for the purposes of subsection (1)—
(a)shall not be required to secure that the requirements of subsections (2) and (3) are satisfied in so far as they relate to any of the intercepted material or related communications data, or any copy of any such material or data, possession of which has been surrendered to any authorities of a country or territory outside the United Kingdom; but
(b)shall be required to secure, in the case of every such warrant, that possession of the intercepted material and data and of copies of the material or data is surrendered to authorities of a country or territory outside the United Kingdom only if the requirements of subsection (7) are satisfied.
(7)The requirements of this subsection are satisfied in the case of a warrant if it appears to the Secretary of State—
(a)that requirements corresponding to those of subsections (2) and (3) will apply, to such extent (if any) as the Secretary of State thinks fit, in relation to any of the intercepted material or related communications data possession of which, or of any copy of which, is surrendered to the authorities in question; and
(b)that restrictions are in force which would prevent, to such extent (if any) as the Secretary of State thinks fit, the doing of anything in, for the purposes of or in connection with any proceedings outside the United Kingdom which would result in such a disclosure as, by virtue of section 17, could not be made in the United Kingdom.
(8)In this section “copy”, in relation to intercepted material or related communications data, means any of the following (whether or not in documentary form)—
(a)any copy, extract or summary of the material or data which identifies itself as the product of an interception, and
(b)any record referring to an interception which is a record of the identities of the persons to or by whom the intercepted material was sent, or to whom the communications data relates,
and “copied” shall be construed accordingly.