If the Secretary of State certifies that in his opinion anything done by a specified person on a specified occasion related to—
national security,
the economic well-being of the United Kingdom, or
the prevention or detection of serious crime,
and was done on behalf of the Crown, the certificate is conclusive evidence that this Act does not apply to any conduct of that person on that occasion.
In subsection (1), "specified" means specified in the certificate in question.
A document purporting to be a certificate under subsection (1) is to be received in evidence and, unless the contrary is proved, be treated as being such a certificate.