Section 27 of the Principal Act is amended -
(a) in subsection (2), in paragraph (e), by substituting "environment," for "environment." and by adding the following to that subsection after that paragraph:
"but, in a case falling within paragraph (a) or (c), the head shall ensure that, before granting the request, the identity of the requester or, as the case may be, the consent of the person is established to the satisfaction of the head.",
and the said subsection (2) (other than paragraphs (b), (d) and (e)), as so amended, is set out in the Table to this section,
and
(b) by inserting the following subsection after subsection (3):
"(4) Where -
(a) a request under section 7 relates to a record to which subsection (1) applies but to which subsections (2) and (3) do not apply or would not, if the record existed, apply, and
(b) in the opinion of the head concerned the disclosure of the existence or non-existence of the record would have an effect specified in subsection (1),
he or she